Virtue or piety is meant to protect and keep oneself from what it fears.
So, the most common use of this word in time of ignorance was in the subject of war and the subsequent discussions of it.
Keeping oneself from war and its probable damages was the main purpose of those people who were always in the expose of danger and invasion of peripheral ethnic groups and tribes.
Military preparedness to protect themselves and the community against successive invasions was the main concern of the people of the time of ignorance..
It was why the prophet used the manner of Warnings of war in his first warnings.
He climbed a mountain and for getting confidence asked people whether or not they believe him if he wanted them to become military ready to face with the invasion of enemy. People's answer was affirmative. Then the prophet said that his warning about Hereafter and the wrath of God was like his warning about invasion of enemy to their soil and boundaries.
In fact as we prepare ourselves against apparent and worldly enemy keeping away from it, we must also keep ourselves away from internal enemy and divine wrath, staying safe from its probable onslaught and potential damage.
In this manner, the Arabic word Taghva (piety), meaning in worldly subjects as keeping away from enemy and its onslaught and potential damage, in divine and spiritual issues finds its similar meaning in a new concept.
Piety, in a complex process, is drawn from a material meaning to supernal meaning, and in Islam and Quran it means keeping ego away from anything which can incite God’s wrath.
If one wants to have such a shield against God’s wrath and Hell, he/she must obey what God states and must act according to Quranic teachings.
So, divine piety or virtue is not only abstain from sin and the vain but also acting according to what God and his prophet order.