And though it is true that one can repent from any sin, avoiding a sin is much easier that trying to sincerely repent from a sin.  Verily, Allah is Forgiving and Merciful to people who perpetrate sins, and He is Merciful, Forbearing, and Beneficent to those who repent.  Beware of this:  That the more Forbearing He becomes towards you, the bolder you become in disobeying Him.

—Sufyān al-Thawrī [d. 161H/778CE]

(Read on pg 165, Salaahud-Deen ibn ‘Alee ibn ‘Abdul-Maujood, The Biography of Sufyaan Ath-Thauree. Darussalam Publishers. Riyadh:2005.)