Firmness and similarity in Quran

Quran states
هُوَ الَّذِي أَنزَلَ عَلَيْكَ الْكِتَابَ مِنْهُ آيَاتٌ مُّحْكَمَاتٌ هُنَّ أُمُّ الْكِتَابِ وَأُخَرُ مُتَشَابِهَاتٌ ۖ فَأَمَّا الَّذِينَ فِي قُلُوبِهِمْ زَيْغٌ فَيَتَّبِعُونَ مَا تَشَابَهَ مِنْهُ ابْتِغَاءَ الْفِتْنَةِ وَابْتِغَاءَ تَأْوِيلِهِ ۗ وَمَا يَعْلَمُ تَأْوِيلَهُ إِلَّا اللَّهُ ۗ وَالرَّاسِخُونَ فِي الْعِلْمِ يَقُولُونَ آمَنَّا بِهِ كُلٌّ مِّنْ عِندِ رَبِّنَا ۗ وَمَا يَذَّكَّرُ إِلَّا أُولُو الْأَلْبَابِ
He it is Who has sent down to thee the Book: In it are verses basic or fundamental (of established meaning); they are the foundation of the Book: others are allegorical. But those in whose hearts is perversity follow the part thereof that is allegorical, seeking discord, and searching for its hidden meanings, but no one knows its hidden meanings except Allah. And those who are firmly grounded in knowledge say: "We believe in the Book; the whole of it is from our Lord:" and none will grasp the Message except men of understanding''.
Lexically, the word ''firmness'' means prevention.
Quran states about beliefs and moral principles
لَّا تَجْعَلْ مَعَ اللَّهِ إِلَٰهًا آخَرَ فَتَقْعُدَ مَذْمُومًا مَّخْذُولًا
Take not with Allah another object of worship; or thou (O man!) wilt sit in disgrace and destitution.
وَقَضَىٰ رَبُّكَ أَلَّا تَعْبُدُوا إِلَّا إِيَّاهُ وَبِالْوَالِدَيْنِ إِحْسَانًا ۚ إِمَّا يَبْلُغَنَّ عِندَكَ الْكِبَرَ أَحَدُهُمَا أَوْ كِلَاهُمَا فَلَا تَقُل لَّهُمَا أُفٍّ وَلَا تَنْهَرْهُمَا وَقُل لَّهُمَا قَوْلًا كَرِيمًا
Thy Lord hath decreed that ye worship none but Him, and that ye be kind to parents. Whether one or both of them attain old age in thy life, say not to them a word of contempt, nor repel them, but address them in terms of honour.
وَاخْفِضْ لَهُمَا جَنَاحَ الذُّلِّ مِنَ الرَّحْمَةِ وَقُل رَّبِّ ارْحَمْهُمَا كَمَا رَبَّيَانِي صَغِيرًا
And, out of kindness, lower to them the wing of humility, and say: "My Lord! bestow on them thy Mercy even as they cherished me in childhood''.
رَّبُّكُمْ أَعْلَمُ بِمَا فِي نُفُوسِكُمْ ۚ إِن تَكُونُوا صَالِحِينَ فَإِنَّهُ كَانَ لِلْأَوَّابِينَ غَفُورًا
Your Lord knoweth best what is in your hearts: If ye do deeds of righteousness, verily He is Most Forgiving to those who turn to Him again and again (in true penitence).
وَآتِ ذَا الْقُرْبَىٰ حَقَّهُ وَالْمِسْكِينَ وَابْنَ السَّبِيلِ وَلَا تُبَذِّرْ تَبْذِيرًا
And render to the kindred their due rights, as (also) to those in want, and to the wayfarer: But squander not (your wealth) in the manner of a spendthrift.
إِنَّ الْمُبَذِّرِينَ كَانُوا إِخْوَانَ الشَّيَاطِينِ ۖ وَكَانَ الشَّيْطَانُ لِرَبِّهِ كَفُورًا
Verily spendthrifts are brothers of the Evil Ones; and the Evil One is to his Lord (himself) ungrateful.
وَإِمَّا تُعْرِضَنَّ عَنْهُمُ ابْتِغَاءَ رَحْمَةٍ مِّن رَّبِّكَ تَرْجُوهَا فَقُل لَّهُمْ قَوْلًا مَّيْسُورًا
And even if thou hast to turn away from them in pursuit of the Mercy from thy Lord which thou dost expect, yet speak to them a word of easy kindness.
وَلَا تَجْعَلْ يَدَكَ مَغْلُولَةً إِلَىٰ عُنُقِكَ وَلَا تَبْسُطْهَا كُلَّ الْبَسْطِ فَتَقْعُدَ مَلُومًا مَّحْسُورًا
Make not thy hand tied (like a niggard´s) to thy neck, nor stretch it forth to its utmost reach, so that thou become blameworthy and destitute.
إِنَّ رَبَّكَ يَبْسُطُ الرِّزْقَ لِمَن يَشَاءُ وَيَقْدِرُ ۚ إِنَّهُ كَانَ بِعِبَادِهِ خَبِيرًا بَصِيرًا
Verily thy Lord doth provide sustenance in abundance for whom He pleaseth, and He provideth in a just measure. For He doth know and regard all His servants.
وَلَا تَقْتُلُوا أَوْلَادَكُمْ خَشْيَةَ إِمْلَاقٍ ۖ نَّحْنُ نَرْزُقُهُمْ وَإِيَّاكُمْ ۚ إِنَّ قَتْلَهُمْ كَانَ خِطْئًا كَبِيرًا
Kill not your children for fear of want: We shall provide sustenance for them as well as for you. Verily the killing of them is a great sin.
وَلَا تَقْرَبُوا الزِّنَا ۖ إِنَّهُ كَانَ فَاحِشَةً وَسَاءَ سَبِيلًا
Nor come nigh to adultery: for it is a shameful (deed) and an evil, opening the road (to other evils).
وَلَا تَقْتُلُوا النَّفْسَ الَّتِي حَرَّمَ اللَّهُ إِلَّا بِالْحَقِّ ۗ وَمَن قُتِلَ مَظْلُومًا فَقَدْ جَعَلْنَا لِوَلِيِّهِ سُلْطَانًا فَلَا يُسْرِف فِّي الْقَتْلِ ۖ إِنَّهُ كَانَ مَنصُورًا
Nor take life - which Allah has made sacred - except for just cause. And if anyone is slain wrongfully, we have given his heir authority (to demand qisas or to forgive): but let him not exceed bounds in the matter of taking life; for he is helped (by the Law).
وَلَا تَقْرَبُوا مَالَ الْيَتِيمِ إِلَّا بِالَّتِي هِيَ أَحْسَنُ حَتَّىٰ يَبْلُغَ أَشُدَّهُ ۚ وَأَوْفُوا بِالْعَهْدِ ۖ إِنَّ الْعَهْدَ كَانَ مَسْئُولًا
Come not nigh to the orphan´s property except to improve it, until he attains the age of full strength; and fulfil (every) engagement, for (every) engagement will be enquired into (on the Day of Reckoning).
وَأَوْفُوا الْكَيْلَ إِذَا كِلْتُمْ وَزِنُوا بِالْقِسْطَاسِ الْمُسْتَقِيمِ ۚ ذَٰلِكَ خَيْرٌ وَأَحْسَنُ تَأْوِيلًا
Give full measure when ye measure, and weigh with a balance that is straight: that is the most fitting and the most advantageous in the final determination.
وَلَا تَقْفُ مَا لَيْسَ لَكَ بِهِ عِلْمٌ ۚ إِنَّ السَّمْعَ وَالْبَصَرَ وَالْفُؤَادَ كُلُّ أُولَٰئِكَ كَانَ عَنْهُ مَسْئُولًا
And pursue not that of which thou hast no knowledge; for every act of hearing, or of seeing or of (feeling in) the heart will be enquired into (on the Day of Reckoning).
وَلَا تَمْشِ فِي الْأَرْضِ مَرَحًا ۖ إِنَّكَ لَن تَخْرِقَ الْأَرْضَ وَلَن تَبْلُغَ الْجِبَالَ طُولًا
Nor walk on the earth with insolence: for thou canst not rend the earth asunder, nor reach the mountains in height.
كُلُّ ذَٰلِكَ كَانَ سَيِّئُهُ عِندَ رَبِّكَ مَكْرُوهًا
. all such things the evil is hateful in the sight of thy Lord
ذَٰلِكَ مِمَّا أَوْحَىٰ إِلَيْكَ رَبُّكَ مِنَ الْحِكْمَةِ ۗ وَلَا تَجْعَلْ مَعَ اللَّهِ إِلَٰهًا آخَرَ فَتُلْقَىٰ فِي جَهَنَّمَ مَلُومًا مَّدْحُورًا
These are among the (precepts of) wisdom, which thy Lord has revealed to thee. Take not, with Allah, another object of worship, lest thou shouldst be thrown into Hell, blameworthy and rejected.
The word '' similarity'' is applied about two things that have same color and form.
When persons in the hell eat the fruits there, they say '' these are same fruits that we used to eat in the word, but Quran states
وَبَشِّرِ الَّذِينَ آمَنُوا وَعَمِلُوا الصَّالِحَاتِ أَنَّ لَهُمْ جَنَّاتٍ تَجْرِي مِن تَحْتِهَا الْأَنْهَارُ ۖ كُلَّمَا رُزِقُوا مِنْهَا مِن ثَمَرَةٍ رِّزْقًا ۙ قَالُوا هَٰذَا الَّذِي رُزِقْنَا مِن قَبْلُ ۖ وَأُتُوا بِهِ مُتَشَابِهًا ۖ وَلَهُمْ فِيهَا أَزْوَاجٌ مُّطَهَّرَةٌ ۖ وَهُمْ فِيهَا خَالِدُونَ
But give glad tidings to those who believe and work righteousness, that their portion is Gardens, beneath which rivers flow. Every time they are fed with fruits therefrom, they say: "Why, this is what we were fed with before," for they are given things in similitude; and they have therein companions pure (and holy); and they abide therein (for ever).
All over Quran is firm. Quran states
الر ۚ كِتَابٌ أُحْكِمَتْ آيَاتُهُ ثُمَّ فُصِّلَتْ مِن لَّدُنْ حَكِيمٍ خَبِيرٍ
A. L. R. (This is) a Book, with verses basic or fundamental (of established meaning), further explained in detail,- from One Who is Wise and Well-acquainted (with all things).
It can be understood from the verses of Quran that all of the verses of Quran are similar;
اللَّهُ نَزَّلَ أَحْسَنَ الْحَدِيثِ كِتَابًا مُّتَشَابِهًا مَّثَانِيَ تَقْشَعِرُّ مِنْهُ جُلُودُ الَّذِينَ يَخْشَوْنَ رَبَّهُمْ ثُمَّ تَلِينُ جُلُودُهُمْ وَقُلُوبُهُمْ إِلَىٰ ذِكْرِ اللَّهِ ۚ ذَٰلِكَ هُدَى اللَّهِ يَهْدِي بِهِ مَن يَشَاءُ ۚ وَمَن يُضْلِلِ اللَّهُ فَمَا لَهُ مِنْ هَادٍ
Allah has revealed (from time to time) the most beautiful Message in the form of a Book, consistent with itself, (yet) repeating (its teaching in various aspects): the skins of those who fear their Lord tremble thereat; then their skins and their hearts do soften to the celebration of Allah´s praises. Such is the guidance of Allah: He guides therewith whom He pleases, but such as Allah leaves to stray, can have none to guide.
The similarity of the verses of Quran means that the verses of Quran have similar content and confirm each other.
There are some topics in Quran that a person cannot understand them with his or her limited knowledge. Quran states
الَّذِينَ يُؤْمِنُونَ بِالْغَيْبِ وَيُقِيمُونَ الصَّلَاةَ وَمِمَّا رَزَقْنَاهُمْ يُنفِقُونَ
Who believe in the Unseen, are steadfast in prayer, and spend out of what We have provided for them.
Purpose from firmness is some verses that represent their meanings very clearly such as the following verses;
قُلْ تَعَالَوْا أَتْلُ مَا حَرَّمَ رَبُّكُمْ عَلَيْكُمْ ۖ أَلَّا تُشْرِكُوا بِهِ شَيْئًا ۖ وَبِالْوَالِدَيْنِ إِحْسَانًا ۖ وَلَا تَقْتُلُوا أَوْلَادَكُم مِّنْ إِمْلَاقٍ ۖ نَّحْنُ نَرْزُقُكُمْ وَإِيَّاهُمْ ۖ وَلَا تَقْرَبُوا الْفَوَاحِشَ مَا ظَهَرَ مِنْهَا وَمَا بَطَنَ ۖ وَلَا تَقْتُلُوا النَّفْسَ الَّتِي حَرَّمَ اللَّهُ إِلَّا بِالْحَقِّ ۚ ذَٰلِكُمْ وَصَّاكُم بِهِ لَعَلَّكُمْ تَعْقِلُونَ
Say: "Come, I will rehearse what Allah hath (really) prohibited you from": Join not anything as equal with Him; be good to your parents; kill not your children on a plea of want;- We provide sustenance for you and for them;- come not nigh to shameful deeds. Whether open or secret; take not life, which Allah hath made sacred, except by way of justice and law: thus doth He command you, that ye may learn wisdom.
وَلَا تَقْرَبُوا مَالَ الْيَتِيمِ إِلَّا بِالَّتِي هِيَ أَحْسَنُ حَتَّىٰ يَبْلُغَ أَشُدَّهُ ۖ وَأَوْفُوا الْكَيْلَ وَالْمِيزَانَ بِالْقِسْطِ ۖ لَا نُكَلِّفُ نَفْسًا إِلَّا وُسْعَهَا ۖ وَإِذَا قُلْتُمْ فَاعْدِلُوا وَلَوْ كَانَ ذَا قُرْبَىٰ ۖ وَبِعَهْدِ اللَّهِ أَوْفُوا ۚ ذَٰلِكُمْ وَصَّاكُم بِهِ لَعَلَّكُمْ تَذَكَّرُونَ
And come not nigh to the orphan´s property, except to improve it, until he attain the age of full strength; give measure and weight with (full) justice;- no burden do We place on any soul, but that which it can bear;- whenever ye speak, speak justly, even if a near relative is concerned; and fulfil the covenant of Allah: thus doth He command you, that ye may remember.
وَأَنَّ هَٰذَا صِرَاطِي مُسْتَقِيمًا فَاتَّبِعُوهُ ۖ وَلَا تَتَّبِعُوا السُّبُلَ فَتَفَرَّقَ بِكُمْ عَن سَبِيلِهِ ۚ ذَٰلِكُمْ وَصَّاكُم بِهِ لَعَلَّكُمْ تَتَّقُونَ
Verily, this is My way, leading straight: follow it: follow not (other) paths: they will scatter you about from His (great) path: thus doth He command you. that ye may be righteous.
Quran states
الرَّحْمَٰنُ عَلَى الْعَرْشِ اسْتَوَىٰ
.(Allah) Most Gracious is firmly established on the throne (of authority)
وَقِيلَ يَا أَرْضُ ابْلَعِي مَاءَكِ وَيَا سَمَاءُ أَقْلِعِي وَغِيضَ الْمَاءُ وَقُضِيَ الْأَمْرُ وَاسْتَوَتْ عَلَى الْجُودِيِّ ۖ وَقِيلَ بُعْدًا لِّلْقَوْمِ الظَّالِمِينَ
Then the word went forth: "O earth! swallow up thy water, and O sky! Withhold (thy rain)!" and the water abated, and the matter was ended. The Ark rested on Mount Judi, and the word went forth: "Away with those who do wrong.
إِلَىٰ رَبِّهَا نَاظِرَةٌ
Looking towards their Lord.
وَوُجُوهٌ يَوْمَئِذٍ بَاسِرَةٌ
.And some faces, that Day, will be sad and dismal
بِئْسَمَا اشْتَرَوْا بِهِ أَنفُسَهُمْ أَن يَكْفُرُوا بِمَا أَنزَلَ اللَّهُ بَغْيًا أَن يُنَزِّلَ اللَّهُ مِن فَضْلِهِ عَلَىٰ مَن يَشَاءُ مِنْ عِبَادِهِ ۖ فَبَاءُوا بِغَضَبٍ عَلَىٰ غَضَبٍ ۚ وَلِلْكَافِرِينَ عَذَابٌ مُّهِينٌ
Miserable is the price for which they have sold their souls, in that they deny (the revelation) which Allah has sent down, in insolent envy that Allah of His Grace should send it to any of His servants He pleases: Thus have they drawn on themselves Wrath upon Wrath. And humiliating is the punishment of those who reject Faith.
وَقَالُوا قُلُوبُنَا غُلْفٌ ۚ بَل لَّعَنَهُمُ اللَّهُ بِكُفْرِهِمْ فَقَلِيلًا مَّا يُؤْمِنُونَ
They say, "Our hearts are the wrappings (which preserve Allah´s Word: we need no more)." Nay, Allah´s curse is on them for their blasphemy: Little is it they believe.
Quran rejects any possibilities of seeing God and states
لَّا تُدْرِكُهُ الْأَبْصَارُ وَهُوَ يُدْرِكُ الْأَبْصَارَ ۖ وَهُوَ اللَّطِيفُ الْخَبِيرُ
No vision can grasp Him, but His grasp is over all vision: He is above all comprehension, yet is acquainted with all things.
It can be understood from the meaning of the above verse that purpose from firm verses are verses that guarantee the principles of the Islam.
Quran has some trains that descended within the understanding of Common people so that all of persons can get familiar with such trains. Descending such trains within the understanding of common people leads to some probabilities about the content of the verse and some of them are in contrast with the principles of Quran. Quran states
إِنَّ رَبَّكَ لَبِالْمِرْصَادِ
. For thy Lord is (as a Guardian) on a watch-tower
وَجَاءَ رَبُّكَ وَالْمَلَكُ صَفًّا صَفًّا
.And thy Lord cometh, and His angels, rank upon rank