MUZZLE. The Mosaic Law forbade the muzzling of oxen when they were treading out the grain, i.e., threshing (Deut.25.4). This was a simple, humane command, in accordance with the kindly spirit of much of the law. Paul makes a curious use of the injunction in 1Cor.9.9 and 1Tim.5.18 where he quotes the command in support of his thesis: “The worker deserves his wages” (niv).
). The Israelites were commanded not to muzzle the ox when it was treading out the grain, i.e., threshing (Deut 25:4
). The muzzle was a guard placed on the mouth of the oxen to prevent them from biting or eating. The threshing ox was to have ample opportunity of feeding, thus making the labor more agreeable. The injunction is in harmony with the spirit of the Deuteronomic exposition of the law of Moses throughout. Paul quotes this injunction in 1 Corinthians 9:8-11
and 1 Timothy 5:17
to illustrate, with an appropriate light touch of humor, his view that “the laborer is worthy of his hire”; i.e., it is proper to pay the minister of the Gospel wages.
International Standard Bible Encyclopedia (1915)
(chacam; phimoo) According to the Deuteronomic injunction (De 25:4), the ox was not to be muzzled while treading the grain, i.e. threshing. The muzzle was a guard placed on the mouth of the oxen to prevent them from biting or eating. The threshing ox would have ample opportunity of feeding (compare Ho 10:11). The Deuteronomic injunction is quite in accordance with the humane spirit which inspires it all through. Paul quotes this law in two places (1Co 9:9; 1Ti 5:18) to illustrate his view that the "laborer is worthy of his hire."