For the Scripture saith - This is adduced as a reason why a church should show all due respect and care for its ministers. The reason is, that as God took care to make provision for the laboring ox, much more should due attention be paid to those who labor for the welfare of the church.
Thou shalt not muzzle the ox - see this passage explained, and its bearing on such an argument shown, in the notes on 1 Corinthians 9:8-10.
And, The labourer is worthy of his reward - This expression is found substantially in Matthew 10:10, and Luke 10:7. It does not occur in so many words in the Old Testament, and yet the apostle adduces it evidently as a quotation from the Scriptures, and as authority in the case. It would seem probable, therefore, that he had seen the Gospel by Matthew or by Luke, and that he quoted this as a part of Scripture, and regarded the Book from which he made the quotation as of the same authority as the Old Testament. If so, then this may be regarded as an attestation of the apostle to the inspiration of the “Gospel” in which it was found.