The LORD make His face shine on you, and be gracious to you;
The LORD lift up His countenance on you, and give you peace.
The LORD said that when the priests bestow the priestly blessing upon the children of Israel, "they shall invoke My name on the sons of Israel, and I then will bless them" (Numbers 6:27). In other words, when the priests pronounce the blessing over the children of Israel, God Himself steps in and offers His blessing.
The first line of the priestly blessing is asking God to bless and keep us; that is, to do good for us, protect us, sustain us, provide for us and rescue us from all evil and distress.
The second line of the priestly benediction asks God to shine His face upon us and to be gracious to us. Rashi explains the shining of God’s face as a beaming, friendly expression. He paraphrases, "May God show you a smiling face." Idiomatically, the shining of God’s face means that He is looking toward us, paying attention to us and taking note of us.
When we ask God to be gracious to us, we are asking Him to find favor in us. The Hebrew word (chanan, חנן) translated as "gracious" can also be translated as "favor." The same concept appears in the Apostolic Scriptures as "grace." Therefore, the priestly blessing is asking for God’s forgiveness for sins and for relationship with Him.
The grace of Messiah is the experience of God’s unmerited favor. Thanks to Messiah, who earned God’s favor, we can be recipients of that favor. God freely forgives our sins and gives us the gift of salvation, eternal life and a share in the world to come "according to the riches of His grace which He lavished on us" (Ephesians 1:7-8).
The priestly benediction saves the best for last: the blessing of peace. The shalom of God that the priestly benediction bestows encompasses the physical, spiritual, mental and emotional realms as well as our relationships with one another, our relationships with family, authorities, employers, employees, neighbors and, most important, our relationship with God. The priestly benediction asks God to smile at us and give us "the peace of God, which surpasses all comprehension" (Philippians 4:7).