What does Psalm 121:5 mean?

Travelers on their way to Jerusalem to observe annual festivals faced difficulties. This could include threats from animals or robbers in the hills (Psalm 121:1–2). Danger also came in the form of the burning rays of a blazing sun. In continuing reassurance (Psalm 121:3–4), these verses note God's provision against these dangers. Like a shepherd, or a caretaker, God "keeps" His people: representing His providence and protection.

God's protection here is symbolized as a shade: something which blocks the punishing rays of the sun (Psalm 91:1). This is a subtle echo of Christ's sacrificial death on the cross: which "blocked" God's wrath on our behalf (Isaiah 53:4–5). In Psalm 57:1 David declared: "Be merciful to me, O God, be merciful to me, for in you my soul takes refuge; in the shadow of your wings I will take refuge, till the storms of destruction pass by." Similarly, the Lord hides believers in the "shadow of his wings" until destructive storms pass by. In his first letter to persecuted believers, Peter said they were guarded by God's power through faith (1 Peter 1:5). Jude 1:24 ascribes praise "to him who is able to keep you from stumbling and to present you blameless before the presence of his glory with great joy."

References to the "right hand" in Scripture typically imply strength and authority. The Lord's right hand speaks of His protection and power. In this case, the psalm seems to speak not of God's right hand, but that of the psalmist. In other words, God is said to be guarding the strength of His people. Psalm 110:5 prophesies concerning the Messiah: "The Lord is at your right hand; he will shatter kings on the day of his wrath."