Deuteronomy 32:5

They have corrupted themselves
This and what follows may seem to be the characters of the enemies of Christ, who lightly esteemed and rejected him, set in a contrast with him; who were not only corrupt by nature, as all men are, but were men of corrupt minds in their tenets and principles; who corrupted the word of God by their traditions, in the times of Christ; and were men of corrupt practices themselves, and corrupters of others:

their spot [is] not [the spot] of his children;
of the children of the divine Person before described; Christ the rock has "children" given him by his Father, in whose adoption he has a concern, and by whose Spirit they are regenerated: these have their "spots"; by which are meant sins, and by those men are stained and polluted; so called in allusion to the spots of animals, as leopards; or to spots in faces and garments, through dirt and the like: by nature they are as others, and while in an unregenerate estate, and indeed after conversion; though they are washed from their sins by the blood of Christ, and are justified by his righteousness, and so without spot, yet in themselves they are not without spots or sins, as their confessions and complaints, and all experience testify: but the spots or sins of wicked men are not like theirs; the children of Christ sin through infirmity of the flesh, and the force of temptation, but wicked men through the malignity of their hearts, willingly and purposely; what good men do of this kind they hate, but what Christless and graceless sinners do they love; saints do not continue in sin, but ungodly men do, and proceed to more ungodliness, and wax worse and worse; gracious souls when they sin, are sorry for it, repent of it, are melted for it, and take shame to themselves on account of it; but unconverted men repent not of their wickedness, are hardened in it, and glory of it; see the character of the Jews in Christ's time, to which this song refers, ( John 8:44 ) ; though these clauses may be rendered to another sense, more agreeably to the context, and to the Hebrew accents, as they are by some; "is there any corruption in him? no" ^F14, that is, is there any corruption in the illustrious Person before described, as without iniquity, just, and right? no, none at all in his nature, divine or human; not in his divine nature, being the incorruptible God; nor in his human nature, which is entirely free from that corruption by sin, common to all that des, tend from Adam by natural generation, he being conceived under the power of the Holy Ghost; nor any in his life and conversation, being perfectly agreeable to the pure and holy law of God; nor any in his doctrines, however they may be charged by ignorant and malicious men, a proof of which follows: or "his children are their spot" ^F15; so the clause may be rendered; the spots of the Jewish nation, the most wicked and vilest among them, became his children; not only the lowest and meanest of them, as to civil and worldly things, but the more ignorant and the more wicked, even publicans and harlots; these, and not the righteous, he came to call and save, and did receive; these were regenerated by his grace, and they believed in him; and to them gave he power to become his children: but then did they remain the wicked persons they had been? no, they were made new creatures, they were internally sanctified, and lived holy lives and conversations; a clear proof this, that there was no corruption in Christ, nor in his doctrine, and that he neither by his tenets nor example encouraged sin, but all the reverse; Wisdom is justified of her children, ( Matthew 11:19 ) ; but then the rest, and the far greater part of the Jewish nation, in his time, have their character truly drawn, as follows:

[they are] a perverse and crooked generation;
men of perverse and crooked natures, tempers, dispositions, ways, and works; who walked contrary to the will and law of God, and were indeed contrary to all men, ( 1 Thessalonians 2:15 1 Thessalonians 2:16 ) ; this is the very character that is given of them, ( Matthew 17:17 ) ( Acts 2:40 ) .