Arise, O LORD, into thy rest; thou, and the ark of thy strength.
Arise, O Lord, into thy rest; thou, and the ark of thy strength. Let thy priests ... thy saints shout for joy (like Psalms 132:1; Psalms 132:10) - from Solomon's prayer at the dedication of the temple (2 Chronicles 6:41). 'The ark of the Lord's strength' (cf. Psalms 78:61) is the ark, the symbol of the strength which "the mighty God of Jacob" (Psalms 132:2) puts forth in behalf of His people. 'For the ark was not a dead ghost, but really showed that God was nigh to His Church' (Calvin). Compare the words of Moses when the ark set forward, and when it rested, wherein the Lord is identified in action with the ark, His symbol (Numbers 10:35-36).
Verse 9. Be clothed with righteousness - "with salvation" in the corresponding Psalms 132:16, and in Solomon's prayer in dedicating the temple. The "righteousness" with which the priests are clothed is that of their justification by God (cf. Isaiah 61:10), which involves with it necessarily their "salvation" (cf. Psalms 24:5).