Deuteronomy 32:4

[He is] the rock
That is, Jehovah is the rock, whose name Moses proposed to publish; and our God, to whom the heavens and the earth are called upon to ascribe greatness, even Christ the rock of salvation: here begins the song; the first word in it is very emphatic; it has a letter in it larger than usual, to denote the greatness of this Person, and to make it observable; he is "this" or "that rock" ^F11, by way of eminence, that rock and stone of Israel, Jacob prophesied of, which was typified by the rock Moses had smitten in the wilderness, and which, no doubt, he knew, as the Apostle Paul did, that it was a type of Christ, and had taught the Israelites so to understand it; and therefore this epithet of a divine Person would not seem strange to them, and yet is that rock the unbelieving Jews would and did stumble at, and the rock of salvation they lightly esteemed and rejected; the rock of refuge for sensible sinners to flee unto for shelter and safety from the wrath and justice of God, and from every enemy; the rock the church of God and every believer are built upon, and in which they dwell; and who is the rock of ages that will endure forever, as the Saviour of his people, and the foundation of their faith and hope:

his work [is] perfect;
not so much the work of creation or of providence, which are both the works of Christ, but that of redemption and salvation, in which there is not only a display of all the divine perfections, but is complete in all its parts; the law is perfectly fulfilled, justice is fully satisfied, a perfect righteousness is wrought out, a complete pardon is procured, perfect peace is made, full atonement of sins obtained, and the whole work is finished; and is so perfect that nothing is wanting in it, or can be added to it, nor can it be unravelled or undone again: likewise the work of building the church on this rock is carrying on, and will be perfected when all the elect of God, all given to Christ and redeemed by his blood, shall be called by grace and gathered in; when the last of the chosen ones, and redeemed of the Lamb, is brought in and laid in the building; when Christ shall deliver up the kingdom to the Father complete, and God shall be all in all, and his church and people will be in a perfect state to all eternity:

for all his ways [are] judgment;
his ways, which he himself has taken and walked in; his ways of providence are according to the best judgment and highest wisdom, and according to the strictest justice and equity; his ways of grace towards the salvation of his people, and the building up his church on himself, the rock; all the methods he took in eternity and time were all formed according to the counsel of God, and planned with the greatest wisdom, founded in his righteous nature, and according to covenant compact with his Father, and entered into in the most honourable manner; and in which he brought about the salvation of his people, in perfect consistence with the justice and holiness of God, and to the honour of them and his holy law: and he has executed all his offices of prophet, priest, and King, in the most just and righteous manner: the ways which he has prescribed his people to walk in, and in which he leads them, are ways of truth, righteousness, and holiness; such are all his ordinances and commandments:

a God of truth; so Christ is called, (See Gill on Isaiah 65:16); or the true God, which also is his name, ( 1 John 5:20 ) ; and is so called in opposition to fictitious deities, and such who are only so by name or office, but not by nature; whereas he is truly and properly God, as appears from his names and nature, from his perfections, works, and worship, ascribed to him: or "God the truth" ^F12, for he is "the truth", ( John 14:6 ) ; the truth of all types, promises, and prophecies, which all have their accomplishment in him; the sum and substance of all truths and doctrines, from whom they all come, and in whom they all centre: or "the God of faith" or "faithfulness" ^F13; the object of faith, and the author and finisher of it; and who is faithful, as the God-man and Mediator, to him that appointed him, being intrusted with all the elect of God, with all promises and blessings of grace for them, with the fulness of grace to communicate unto them, with the glory of God in their salvation, and with their future and final happiness; and is faithful in the discharge of his offices of prophet, priest, and King:

and without iniquity;
in his nature, in his heart, in his lips, and in his life; nor was ever any committed by him:

just and right [is] he;
just, both as a divine Person, and as man and Mediator; a lover and doer of righteousness, a worker out of righteousness for his people, and the justifier of them by it; just and righteous, as the, servant of God, as King of saints, and Judge of the whole world; "right" or "upright", which is the character of a divine Person, agrees with Christ, and may denote his sincerity, uprightness, and faithfulness.