Psalms 50:5

“That I may see the good of thy chosen, etc.] The elect, according to the foreknowledge of God; who are chosen in Christ to holiness and happiness, through sanctification of the Spirit, and belief of the truth unto salvation by him; the vessels of mercy afore prepared unto glory, both of Jews and Gentiles. The “good” of those is not any goodness of their own, for there is none in them naturally; they are by nature no better than others, none are good, nor do good, no, not one: but the goodness of God laid up for them, and bestowed on them; the blessings of goodness with which Christ is preparing for them; all the good things secured for them in a well ordered covenant; which they partake of…”

“my saints-- (Psa 4:3). made--literally, "cut" a covenant, &c.--alluding to the dividing of a victim of sacrifice, by which covenants were ratified, the parties passing between the divided portions (compare Gen 15:10, Gen 15:18).”

“Gather my saints together unto me - This is an address to the messengers employed for assembling those who are to be judged. Similar language is used by the Saviour Matthew 24:31 : “And he (the Son of Man) shall send his angels with a great sound of a trumpet, and they shall gather together his elect from the four winds, from one end of heaven to the other.” The idea is, that God will bring them, or assemble them together. All this is language derived froth the notion of a universal judgment, “as if” the scattered people of God were thus gathered together by special messengers sent out for this purpose. The word “saints” here refers to those who are truly his people. The object - the purpose…”

“Gather - O ye angels, summon and fetch them to my tribunal. Which is poetically spoken, to continue the metaphor, and representation of the judgment. My saints - The Israelites, whom God had chosen and separated them from all the nations of the earth, to be an holy and peculiar people to himself, and they also had solemnly devoted themselves to God; all which aggravated their apostacy. Those - Who have entered into covenant with me, and have ratified that covenant by sacrifice. This seems to be added, to acquaint them with the proper nature, use and end of sacrifices, which were principally appointed to be signs and seals of the covenant made between God and his people; and consequently to…”

“Gather: Mat 24:31; Th1 4:16, Th1 4:17; Th2 2:1 my saints: Psa 97:10; Deu 33:2, Deu 33:3; Pro 2:8; Isa 13:3; Zac 14:5; Co1 6:2, Co1 6:3; Th1 3:13; Jde 1:14 made: Exo 24:3-8; Mat 26:28; Heb 9:10-23, Heb 12:24, Heb 13:20 Psalms 50:6”