A Sign Of Perfection Of Worship

It is stated by Hazrat Thauban (ra) that when the Messenger of Allah (saws) finished offering his prayers, he sought forgiveness of Allah three times

[Muslim]

Explanation : This hadith tells us that after the Prophet (saws) would say "Astagfirullah" three times.  In fact, it is a sign of perfection of worship that a man having offered prayers considers his eforts imperfect and regards himself responsible for that.So, he seeks the forgiveness of Allah.

Taubah (repentance) and Istighfaar (seeking forgiveness from Allah) are among the most meritorious acts of virtue for the believers. Taubah means feeling remorse for our actions or omissions.Istighfar means expressing that remorse in words and begging Allah for forgiveness. The act for which we perform taubah and istighfar is not necessarly a sin or an act of disobedienceto Allah, it also includes our shortcomings.

As we realise Allah's immense favours to us, all our thankfulness and devotion clearly appears to be inadequate.As we realise the Grandeur of Allah, Most High, our acts of worship and obedience are clearly seen to be insufficient.

The higher a person is on the scale of piety and taqwa, the greater is this sense of inadequacy. Consequently the greater is his practice of Istighfar.