There are ~105 benedictions/blessings in the Bible. I’ll share a summary of the why from the Pastor at Christ United Reformed Church. You can read the full blog post here.
Why does the minister raise his hands at the end of the worship service and pronounce a blessing on the people of God? Where does this practice come from? Many Christians are unclear on the meaning of the benediction and treat it as little more than a pious way of saying, “That’s all folks. The service is over.”
The benediction is God’s good word to us. That’s essentially what benediction means. It is a compound word from Latin: bene, which means ‘good,’ and dicere, which means ‘to speak.’ From that comes the Latin word benedictio, which means “blessing.” It is a pronouncement of God’s blessing upon his people.
This practice originated in the old covenant. The Lord commanded Aaron, the high priest, to bless the people with these words: “The LORD bless you and keep you; The LORD make His face to shine upon you, and be gracious to you; The LORD lift up His countenance upon you and give you peace”. The high priest would lift his hands in a posture of peace... Now, in the new covenant, Christ blesses us in his name. The name of the LORD is more fully manifested in that name above every name: the Lord Jesus Christ, YHWH Incarnate... Each week, our great High Priest in heaven sends us an ambassador to pronounce his blessing upon us. A minister of the Gospel has been given the responsibility to lift his hands and declare the blessing of Christ to the people of Christ. The minister is not the source of the blessing; Christ is. And yet, Christ uses human means by the power of the Holy Spirit to bring that blessing to his people.
This is God’s final word to us in the covenant assembly of worship. God tells us that, because of Christ, we are not under his judgement, but under his grace and the objects of his love. The benediction is God’s holy announcement that our whole life is covered by his grace. --- Now may the Lord of peace himself give you peace at all times in every way. The Lord be with you all. 2 Thess 3:16 | ESV