1 Timothy 5:18

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.