Every good thing that I have is only because I have received it; from someone who loves me far more than I know, or will ever know. How do I know this? Because He died for me and shed His blood for me so that I could live completely free of guilt and shame, as a new creature. It is not my emotions that tell me this or something that I feel, it is by faith alone.
I am crucified with Christ: nevertheless I live; yet not I, but Christ liveth in me: and the life which I now live in the flesh I live by the faith of the Son of God, who loved me, and gave himself for me. Galatians 2:20
Why did God my Father give His only begotten son for me? …and all this out of pure, fatherly, divine goodness and mercy, without any merit or worthiness in me
It is of the LORD's mercies that we are not consumed, because his compassions fail not. They are new every morning: great is thy faithfulness. The LORD is my portion, saith my soul; therefore will I hope in him. The LORD is good unto them that wait for him, to the soul that seeketh him. It is good that a man should both hope and quietly wait for the salvation of the LORD. Lamentations 3:22-26
I can give God nothing to repay Him for the death of His son, nothing. But I can give my neighbor something - I can give them the words that Christ gave me, I can proclaim to them what Jesus has done, is doing and will continue to do for me and for them.
Why should we remember and proclaim His death?
First, so that we may learn to believe that no creature could make satisfaction for our sins. Only Christ, true God and man, could do that. Second, so we may learn to be horrified by our sins, and to regard them as very serious. Third, so we may find joy and comfort in Christ alone, and through faith in Him be saved. (Martin Luther – The Large Catechism)