6:24 The Lord bless you. God blesses by giving good harvests, peace, children, and his own presence (Lev. 26:3–13). keep. That is, “guard” and “protect.”
6:25 his face to shine upon you. God’s presence is like sunshine (Ps. 19:1–11). A shining face is a smiling face, a pledge of God’s good favor (Ps. 80:3, 7, 19).
6:26 The “countenance” is the face or the expression of one’s face. For God to lift up his countenance involves taking notice of and treating his people with favor. Peace (Hb. shalom) involves more than the English sense of “lack of war”; it means total well-being.
ESV Study Bible
6:24–26 This threefold, divinely inspired blessing was pronounced by the priest with uplifted hands (Lev. 9:22). It moves from a general blessing (v. 24), to an invocation of God’s favor and presence (v. 25), and finally to a climactic mention of the peace that comes only with God’s gracious presence (v. 26). The pronouncement of this blessing placed God’s covenant name Lord (Yahweh) on the people (v. 27).
Reformation Study Bible