(18) For the scripture saith, Thou shalt not muzzle the ox that treadeth out the corn.--The quotation is from Deuteronomy 25:4.

The idea in the Apostle's mind, when he quoted the words of Moses, was: If, in the well-known and loved law of Israel, there was a special reminder to God's people that the very animals that laboured for them were not to be prevented from enjoying the fruits of their labours, surely men who with zeal and earnestness devoted themselves as God's servants to their fellows, should be treated with all liberality, and even dignified with especial respect and honour.

And, The labourer is worthy of his reward.--It is possible, though hardly likely, that St. Paul, quoting here a well-known saying of the Lord (see St. Luke 10:7), combines a quotation from a Gospel with a quotation from the Book of Deuteronomy, introducing both with the words "For the Scripture saith"--Scripture (graphe) being always applied by St. Paul to the writings of the Old Testament. It is best and safest to understand these words as simply quoted by St. Paul, as one of the well-remembered precious declarations of the Lord Jesus.

Verse 18. - When he for that, A.V.; hire for reward, A.V. Thou shall not muzzle, etc. This passage, kern Deuteronomy 25, which is quoted and commented upon, in the same souse as here, in 1 Corinthians 9:9, shows distinctly that reward was to go with labor. The ox was not to be hindered from eating some portion of the grain which he was treading out. The preacher of the gospel was to live of the gospel. The laborer is worthy of his hire (ἄξιος ὁ ἐργάτης τοῦ μισθοῦ αὑτοῦ). In Matthew 10:10 the words are the same as here, except that τῆς τροφῆς (his meat) is substituted for τοῦ μισθοῦ. But in Luke 10:7 the words are identical with those here used, even to the omission (in the R.T.) of the verb ἔστιν. The conclusion is inevitable that the writer of this Epistle was acquainted with and quoted from St. Luke's Gospel; and further, that he deemed it, or at least the saying of the Lord Jesus recorded, in it, to be of equal authority with "ἡ γραφή," the Scripture. If this Epistle was written by St. Paul after his first imprisonment at Rome, we may feel tolerably certain that he was acquainted with the Gospel or St. Luke, so that there is no improbability in his quoting from it. His reference to another saying of the Lord Jesus in Acts 20:35 gives additional probability to it. The passage in 2 Timothy 4:18 seems also to be a direct reference to the Lord's Prayer, as contained in the Gospels of St. Matthew and St. Luke. St. Paul does not directly call the words ἡ γραφή, only treats them as of equal authority, which, if they were the words of Christ, of course they were.

5:17-25 Care must be taken that ministers are maintained. And those who are laborious in this work are worthy of double honour and esteem. It is their just due, as much as the reward of the labourer. The apostle charges Timothy solemnly to guard against partiality. We have great need to watch at all times, that we do not partake of other men's sins. Keep thyself pure, not only from doing the like thyself, but from countenancing it, or any way helping to it in others. The apostle also charges Timothy to take care of his health. As we are not to make our bodies masters, so neither slaves; but to use them so that they may be most helpful to us in the service of God. There are secret, and there are open sins: some men's sins are open before-hand, and going before unto judgment; some they follow after. God will bring to light the hidden things of darkness, and make known the counsels of all hearts. Looking forward to the judgment-day, let us all attend to our proper offices, whether in higher or lower stations, studying that the name and doctrine of God may never be blasphemed on our account.In Deuteronomy 25:4

thou shalt not muzzle the ox that treadeth out the corn; See Gill on 1 Corinthians 9:9. See Gill on 1 Corinthians 9:10. The ox, for its strength and labour, is a fit emblem of a Gospel minister; and its treading the corn out of the husk and ear aptly represents the beating out, as it were, of Gospel truths, by the ministers of it, their making the doctrines of the Gospel clear, plain, and evident to the understandings of men; wherefore, as the ox was not muzzled when it trod out the corn, but might freely and largely feed upon it, so such who labour in the preaching of the Gospel ought to have a sufficient and competent maintenance: for which purpose this citation is made, as also the following:

and the labourer is worthy of his reward; which seems to be taken from Luke 10:7 which Gospel was now written, and in the hands of the apostle; who here, by two testimonies, the one from Moses, and the other from Christ, supports the right of the honourable maintenance of the ministers of the Gospel.