In Psalm 89:13, God's own mighty arm is described — the same power that strengthens His anointed in verse 21.

Psalm 18:32-39 describes God strengthening David for battle, mirroring the promise of divine support in Psalm 89:21.

Psalm 80:17 asks God's hand to be on the man of His right hand, whom He made strong — directly parallel to the anointed strengthened here.

2 Samuel 7:8-16 is the Davidic covenant where God promises to establish David's throne, the basis for Psalm 89:21's assurance.

2 Samuel 7:13 is the original covenant promise that David's throne would be established — the foundation for the strengthening here.

Lamentations 4:20 refers to the anointed of the LORD being captured — a stark contrast to the strengthened anointed in Psalm 89:21.