Psalm 43
Psa 43:1-5. Excepting the recurrence of the refrain, there is no good reason to suppose this a part of the preceding, though the scope is the same. It has always been placed separate.
Judge - or, "vindicate" (Psa 10:18).
plead, etc. - (Psa 35:1).
ungodly - neither in character or condition objects of God's favor (compare Psa 4:3).

God of my strength - by covenant relation my stronghold (Psa 18:1).
cast me off - in scorn.
because - or, "in," that is, in such circumstances of oppression.

light - as in Psa 27:1.
truth - or, "faithfulness" (Psa 25:5), manifest it by fulfilling promises. Light and truth are personified as messengers who will bring him to the privileged place of worship.
tabernacles - plural, in allusion to the various courts.

the altar - as the chief place of worship. The mention of the harp suggests the prominence of praise in his offering.