"But Joseph said to them, 'Don't be afraid. Am I in the place of God? You intended to harm me, but God intended it for good to accomplish what is now being done, the saving of many lives. So then, don't be afraid. I will provide for you and your children.' And he reassured them and spoke kindly to them."
Have you ever done something terrible to someone and years later still felt shame and regret? Were you still trying to make amends to the person even when that person had already forgiven you? How about your memories from your past that you still bring before God even though you have asked Him to forgive you?
In Genesis 50, we see Joseph and his brothers having a conversation when their father Jacob had died. You can see that Joseph's brothers still felt the guilt, shame, and regret they shared because of saling Joseph into slavery. As we see, Joseph already had forgiven his brothers because of God's sovereignty in the situation. Joseph realized that God allowed these things to happen to him for a higher purpose, "the saving of many lives." 
In our lives we have done some despicable things that we are ashamed of and are still dealing with lingering effects of regret. We don't have to allow these feelings to control us. We can live in the freedom that God has given us through the sacrifice of His son, Jesus. If we have asked God for forgiveness, then the Bible says in Hebrews 8:12-"For I (God) will forgive their wickedness and will remember their sins no more." God no longer will bring that offence up to you because He chooses to remember it no more. That is great news.
I had a friend that told me when he would go to God in prayer, the shame and regret of a past sin would always come to his mind. When this would happen, he would ask God to forgive him even though he knew he had already been forgiven of it several years earlier. One day when he asked God to forgive that sin, he felt the Lord impress on his heart that God did not know what he was talking about. To God the repentant and forgiven sin no long was in God memory. 
Regret, guilt and shame are all tools the enemy uses to condemn us to try and hinder us from walking in God's peace and rest. Today if you are still feeling defeated by past sins take courage that a confessed sin to God is a forgiven sin. He doesn't know what you are talking about. 
Prayer: Dear Lord, Thank you for your grace and forgiveness that releases me from the regrets of my past. I receive all that you have for us as we walk in the freedom you provide. In Jesus' name, Amen!