1 Kings 13:12

Lord, by sacrifices.

Holocaust. Hebrew, "I forced myself therefore," &c. It is asked whether Saul offered sacrifice, or caused it to be offered by the priests. The text seems to assert that he did it himself. Samuel and David did the like; and we read that Solomon ascended to the brazen altar, at Gabaon, for the same purpose, 2 Paralipomenon i. 5. If it was lawful to erect altars out of the tabernacle, notwithstanding the divine prohibition, why might not individuals also offer sacrifice on certain solemn occasions? The Hebrew kings seem to have exercised some of the sacerdotal functions, particularly before the building of the temple; for afterwards we find one of their kings severely punished for presuming to offer incense, 4 Kings xv. 5. (Calmet)

Yet the proofs that they ever lawfully offered sacrifice, are not very satisfactory, as, in the Scripture language, a person is often said to do what he enjoins another to perform on his account; and if some prophets have acted in the character of priests, by divine dispensation, we need not extend the privilege to all who have dared to assume the like prerogative. The law is clear. It is the duty of all who do not regulate their conduct by it, to know that they have God's approbation. Their expressing no scruple on the occasion, proves nothing, no more than the sacred writer's omitting to stigmatize their proceedings. But here, if Saul really offered the holocaust, the words of Samuel, Thou hast done foolishly, convey a sufficient reproach: but if he did not, we must suppose that he blames the neglect of waiting the full term of days. (Haydock)