John Gill Commentary Acts 15:32

"And Judas and Silas, being themselves also prophets, exhorted the brethren with many words, and confirmed them." — Acts 15:32 (ASV)

And Judas and Silas being also prophets themselves
As well as Paul and Barnabas, and others, that were at Antioch; see (Acts 13:1) and by prophets are meant, not only such who had the gift of foretelling things to come; though such there were, and these might have that gift; but such who were able to explain the prophecies of the Old Testament, give the true sense of the Scriptures, and open them to the edification of others; wherefore having such gifts, they made use of them; Beza's ancient copy adds, "full of the Holy Ghost":

and exhorted the brethren with many words ; which does not so much design the prolixity of their discourses, and the frequency of their ministrations, though they might preach both long and often; as the richness of the matter of them, as the Syriac version suggests, rendering it, "with a rich word"; with copiousness, fulness, and abundance of Gospel truths, with which they comforted the brethren, giving them many useful instructions and exhortations:

and confirmed them ; in the doctrines of the Gospel, and particularly in their Christian liberty, and freedom from the law of Moses, in which the false teachers had endeavoured to stagger them.