Verses 1-4
Psalm 50:1-23. In the grandeur and solemnity of a divine judgment, God is introduced as instructing men in the nature of true worship, exposing hypocrisy, warning the wicked, and encouraging the pious.
The description of this majestic appearance of God resembles that of His giving the law (compare Exodus 19:16; Exodus 20:18; Deuteronomy 32:1).
Verse 4
above — literally, “above” (Genesis 1:7).
heavens … earth — For all creatures are witnesses (Deuteronomy 4:26; Deuteronomy 30:19; Isaiah 1:2).
Verse 5
my saints — (Psalm 4:3).
made — literally, “cut”
a covenant, etc. — alluding to the dividing of a victim of sacrifice, by which covenants were ratified, the parties passing between the divided portions (compare Genesis 15:10, Genesis 15:18).
Verse 6
The inhabitants of heaven, who well know God‘s character, attest His righteousness as a judge.
Verse 7
I will testify — that is, for failure to worship aught.
thy God — and so, by covenant as well as creation, entitled to a pure worship.
Verses 8-15
However scrupulous in external worship, it was offered as if they conferred an obligation in giving God His own, and with a degrading view of Him as needing it [Psalm 50:9-13 ]. Reproving them for such foolish and blasphemous notions, He teaches them to offer, or literally, “sacrifice,” thanksgiving, and pay, or perform, their vows - that is, to bring, with the external symbolical service, the homage of the heart, and faith, penitence, and love. To this is added an invitation to seek, and a promise to afford, all needed help in trouble.
Verses 16-20
the wicked — that is, the formalists, as now exposed, and who lead vicious lives (compare Romans 2:21, Romans 2:23). They are unworthy to use even the words of God‘s law. Their hypocrisy and vice are exposed by illustrations from sins against the seventh, eighth, and ninth commandments.
Verse 21-22
God, no longer (even in appearance) disregarding such, exposes their sins and threatens a terrible punishment.
Verse 22
forget God — This denotes unmindfulness of His true character.
Verse 23
offereth praise — (Psalm 50:14), so that the external worship is a true index of the heart.
ordereth … aright — acts in a straight, right manner, opposed to turning aside (Psalm 25:5). In such, pure worship and a pure life evince their true piety, and they will enjoy God‘s presence and favor.