Reason Not To Sin - 1 Peter 1:14

As obedient children, not fashioning yourselves according to the former lusts in your ignorance:
1 Peter 1:14, KJV

Why not sin?

First, let me ask: do you or don't you want to be obedient? You may go through a time when you know what is right but aren't ready to do it. But if you do have a desire somewhere inside you to eventually submit and obey God, consider this: the lusts in which you may indulge—however heinous or not—are things associated with ignorance. Ignorance of God and ignorance of the soul-damaging characteristic of sin. But you are not now ignorant

Or do you not know the love of God that sought you out long before you were born, that died on the cross for the sins which you may even now entertain? All your sins were still in the future when Jesus gave up His life for you. You are now fully accepted. You are brand new, created according to new things! So don't fashion yourself according to old lusts!