Luke 2:21, “And at the end of eight days, when He was circumcised, He was called Jesus, the name given by the angel before He was conceived in the womb.”
Circumcision was the mark of God’s covenant with Israel that He made with Abraham, Isaac, and Jacob (His Old Testament, i.e. old covenant), which was customary to do for male children who were 8-days-old. This mark of the covenant was God taking away their original sin for the sake of the promised Messiah. Jesus, fully man and fully God, was able to live the perfect life in obedience to the Law that we are incapable of fulfilling. The Law reveals to us God’s perfect holiness, which reciprocally reveals to us our inability to be holy by ourselves—that is, it reveals our sinfulness. The Law required a perfect man to fulfil it, thus Jesus was born fully man in Mary’s womb. However, only God can fulfil the Law, so it was required that God come down as a man to fulfil it, thus Jesus is also fully God born of the Holy Spirit (John 1:1, 14; 8:58; 10:30, 33).
Every year in Old Testament Israel, there was a specific day set aside called the Day of Atonement. On this day, the high priest would sacrifice a goat as a sin offering (forgiveness of sins) for the entire people of Israel (see Leviticus 16). After giving these instructions to Moses, God said, “For the life of the flesh is in the blood, and I have given it for you on the altar to make atonement for your souls, for it is the blood that makes atonement by life… For the life of every creature is its blood: its blood is its life” (Leviticus 17:11, 14). And so Jesus shed His blood for us on the cross—having fulfilled the Law perfectly, He sacrificed Himself as the blood atonement for all our sins, having died once for all (Romans 6:10). We therefore partake in the Lord’s Supper for forgiveness of sins, finding atonement in His blood: “Truly, truly, I say to you, unless you eat the flesh of the Son of Man and drink His blood, you have no life in you. Whoever feeds on My flesh and drinks My blood has eternal life, and I will raise him up on the last day” (John 6:53-54).
Furthermore, we are baptised in the new covenant of Jesus Christ as we also baptise our infants in receiving the forgiveness of original sin and the gift of the Holy Spirit just as the Israelites circumcised their children into the covenant of God, and we continue to instruct our children in the Lord as they age as we also continue in our daily baptism to “purge away whatever is of the old Adam, and that which belongs to the new man may come forth” (LC, Baptism, 65). You may have made a New Year’s resolution this year, but we don’t need one day of the year to start over like the Israelites did. No, we have the forgiveness of sins through our Lord and Saviour Jesus Christ who, in our baptism, empowers us in the Holy Spirit to start fresh every day. Thanks be to God the Father who sent His Son to be the propitiation for our sins.