In the Holy Qur'an

Surely Allah loves those who turn much to Him (in repentance), and He loves those who purify themselves (2:222)

But if they repent and keep up prayer and pay the poor-rate, they are your brethren in faith (9:11)

In the Traditions

The Prophet said, "Allah is more delighted when a slave turns to Him than when a man finds his riding-beast and provisions after they have gone astray during a dark night"

The Prophet said, "There is nothing more beloved to Allah than a youth who turns to Him"

Imam Ali said, "All good is contained in 3 things: your looking, your silence and your speech. Looking without reflection is negligence, silence without mediation is unmindfulness, and speech without remembrance is idle talk. Happiness will be theirs whose looking is a lesson, whose silence is mediation, whose speech is remembrance, who weep because of their mistakes and by whose hand people are safe from evil."