Colossians 2:13 When you were dead in your sins and in the uncircumcision of your flesh, God made you alive with Christ. He forgave us all our sins,  

What a reassuring reminder! God has forgiven all my sins. I am completely forgiven and made alive in Christ.

If, after having confessed Jesus as your Lord with your mouth at baptism, you still think of something in your life that suddenly makes you feel guilty and ashamed and burdened, then you need to remind yourself of what God says to you.

God has done all that is needed to take your guilt from you and wrap you with garments of righteousness. Then why should you keep living with a burden that is not yours anymore? Would it not be better to shout with joy, every time we remember our iniquity, that yes! yes! I have been washed by the blood that was shed on Calvary. He has removed our sins that was red like crimson/scarlet and made us white as snow/wool (Isaiah 1:18).

Because there is no condemnation for those in Christ Jesus (Romans 8:1), you need to be gratefully confident if you have believed in Jesus and agreed that yes, what you have done was iniquity and have decided to turn away from your old life and walk towards God. 

Because God is greater than our hearts and he knows everything (1 John 3:20), let us accept his grace and joyfully live as children of God. Let us not allow any false guilt to weigh us down nor listen to the voice of the accuser, but let us be grateful that the guilt of our sins has been nailed to the cross triumphantly by Christ and we have been healed by his wounds. (1 Peter 2:24) 

So today…think of something that you wish you had never done or something you just want to forget since it makes you cringe at yourself, take it to Jesus and receive his forgiveness that is provided through his precious blood (1 John 1:7). Or maybe, there is something you have never been able to talk about, decide to bring it in the light and confess any deed of darkness, he is just and will cleanse you of all unrighteousness (1 John 1:9).