For I testify again - Probably he had stated this when he had preached the gospel to them first, and he now solemnly bears witness to the same thing again. Bloomfield, however, supposes that the word "again" here (πάλιν palin) means, on the other hand, or, "furthermore," or, as we would say, "and again."

That he is a debtor to do the whole law - He binds himself to obey all the Law of Moses. Circumcision was the distinguishing badge of the Jews, as baptism is of Christians. A man, therefore, who became circumcised became a professor of the Jewish religion, and bound himself to obey all its special laws. This must be understood, of course, with reference to the point under discussion; and means, if he did it with a view to justification, or as a thing that was necessary and binding. It would not apply to such a case as that of Timothy, where it was a matter of mere expediency or prudence; see the note at Galatians 5:2.

He is a debtor to do the whole law - Lays himself, by receiving circumcision, under the obligation to fulfill all its precepts, ordinances, etc.

For I testify again to every man,.... This is the form of an oath, a calling God to witness, swearing by the living God, and declaring as in his presence to every man, whether Jew or Gentile, whoever he be:

that is circumcised; in order to obtain salvation, and as necessary to it:

that he is a debtor to do the whole law; and this it is that made circumcision an insupportable yoke, for that itself might be bore, and was bore by children of eight days old; but the fulfilling of the whole law cannot be done by any man; and yet everyone that is circumcised, in order to procure righteousness and life, is bound to keep the whole law; because the law is only his righteousness, when he observes all that is required in it, and as the Lord has commanded; if he does not, he is pronounced accursed: and this proves what was before said, that Christ is of no profit to such persons; because they reject him and his righteousness, and, as much as in them lie, make void his obedience, sufferings, and death: hence the same thing is repeated, though not in the same words, in the next verse.

Again (πάλιν)

Probably with reference to what he had said at his last visit.

Every man

Emphasizing and particularising the general to you, you, in Galatians 5:2.

A debtor (ὀφειλέτης)

In N.T. mostly of one under moral obligation. So in the sense of sinner, Matthew 6:12; Luke 13:4. Comp. Romans 1:14; Romans 8:12. Similarly the verb ὀφείλειν to owe, as Luke 11:4; Luke 17:10; Romans 15:1, etc., though it is frequent in the literal sense.

To do the law (ποιῆσαι)

Rare in N.T. See John 7:19; Romans 2:13, Romans 2:25 (πράσσῃς). Τηρεῖν to observe the law, the tradition, the commandment, Matthew 19:17; Mark 7:9; John 14:15; Acts 15:5 James 2:10 : πληροῦν to fulfill the law, Romans 13:8; Galatians 5:14; comp. ἀναπληροῦν Galatians 6:2 : φυλάσσειν to keep or guard the law, Acts 7:53; Acts 21:24; Galatians 6:13 : also with commandments, word of God or of Christ, ordinances of the law, Matthew 19:20; Mark 10:20; Luke 11:28; John 12:47; Romans 2:26. Τελεῖν to carry out the law, Romans 2:27; James 2:8. Ποιῆσαι is to perform what the law commands: τηρεῖν to observe, keep an eye on with the result of performing: φυλάσσειν to guard against violation: τελεῖν to bring to fulfillment in action.

The whole law (ὅλον)

Comp. James 2:10. Submission to circumcision commits one to the whole law. It makes him a party to the covenant of the law, and the law requires of every one thus committed a perfect fulfillment, Galatians 3:10.

For I testify again to every man that is circumcised, that he is a debtor to do the whole law.

5:3 I testify again to every man that is circumcised. He shows them that if one becomes circumcised to keep the law of Moses,

that he is a debtor to do the whole law. That he is placed under obligation to keep the whole law, since other commandments are equally binding.

5:3 I testify to every man - Every gentile. That is circumcised - He thereby makes himself a debtor - Obliges.

3. For-Greek, "Yea, more"; "Moreover."

I testify . to every man-as well as "unto you" (Ga 5:2).

that is circumcised-that submits to be circumcised. Such a one became a "proselyte of righteousness."

the whole law-impossible for man to keep even in part, much less wholly (Jas 2:10); yet none can be justified by the law, unless he keep it wholly (Ga 3:10).

5:1-6 Christ will not be the Saviour of any who will not own and rely upon him as their only Saviour. Let us take heed to the warnings and persuasions of the apostle to stedfastness in the doctrine and liberty of the gospel. All true Christians, being taught by the Holy Spirit, wait for eternal life, the reward of righteousness, and the object of their hope, as the gift of God by faith in Christ; and not for the sake of their own works. The Jewish convert might observe the ceremonies or assert his liberty, the Gentile might disregard them or might attend to them, provided he did not depend upon them. No outward privileges or profession will avail to acceptance with God, without sincere faith in our Lord Jesus. True faith is a working grace; it works by love to God, and to our brethren. May we be of the number of those who, through the Spirit, wait for the hope of righteousness by faith. The danger of old was not in things of no consequence in themselves, as many forms and observances now are. But without faith working by love, all else is worthless, and compared with it other things are of small value.