What’s importance of piety (Taqwa) in human life?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, sallallaahu ‘alayhi wa sallam, is His slave and Messenger.

To fear Allah is what Allah has advised all the people, the ancient generations and the contemporary ones, Allah Says (what means): {…And verily, We have recommended to the people of the Scripture before you, and to you (O Muslims) that you (all) fear Allah, and keep your duty to Him,…} [Quran 4:131]

It is also the advice of the Prophet to his companions as he said: "I advise you to fear Allah." [Reported by Abu Daawood and At-Tirmithi, and narrated by Irbadh bin Sariya ]  So both the verse of Allah, and the Hadeeth of the Prophet show the importance and excellence of Taqwa (piety/fear of Allah).  Al Taqwa means to put between yourself and the punishment of Allah a protection, by abiding by the Laws (Orders) of Allah and refraining from what Allah has forbidden.

The results of Taqwa are many, and could be summarized as follows:

1) Al Taqwa is a means of being admitted to Paradise.  Allah says (what means): {Such is the Paradise which We shall give as an inheritance to those of Our slaves who have been Al-Muttaqoon (pious and righteous persons)} [Quran 9:63]

2) Al Taqwa is a way of overcoming troubles and gaining provision.  Allah says (interpretation of meaning): {…And whosoever fears Allah and keeps his duty to Him, He will make a way for him to get out (from every difficulty). And He will provide him from (sources) he never could imagine. …} [Quran 65:2-3]

3) It is a way of rendering what is difficult easy, Allah says (interpretation of meaning): {…and whosoever fears Allah and keeps his duty to Him, He will make his matter easy for him.} [Quran 65:4]

4) It is a means of being happy in this life and in the Hereafter. Happiness is not by saving money (and wealth) but happiness is to be pious.

5) It is a way of being protected from the plots of unbelievers.  Allah says (interpretation of meaning): {…But if you remain patient and become Al-Muttaqoon (the pious), not the least harm will their cunning do to you….} [Quran 3:120]

There are a lot of other results that could be discovered by reading the texts of the Quran and Sunnah.

Allah knows best.