The psalmist began by repeating part of Israel"s priestly blessing (cf. Numbers 6:24-26) to request God"s favor on His people. Causing one"s face to shine on others means smiling on them with favor and approval (cf. Psalm 4:6). The writer requested God"s blessing on Israel so that other nations would learn of His favor, turn to Him in faith, and experience His salvation themselves (v2). [source][source][source]