Quoting Commentary for I Kings 18:36

כי יקום בקרבך נביא, "When a prophet arises in your midst, etc." The word נביא implies that even if this person has an established reputation as a true prophet, if he asks you to violate any of G'd's commandments even temporarily and it involves idolatry he is guilty of death. [He may ask you to temporarily violate a different one of the commandments such as Elijah at Mount Carmel who rebuilt a private altar upon which it was forbidden to offer sacrifices after the Temple in Jerusalem had been built. Ed.]

כחצות הלילה means, WHEN THE NIGHT IS DIVIDED (i. e., when midnight arrives). כחצות is an infinitive with prefix, of similar form to, (1 Kings 18:36) בעלות, “when went up” and (Psalms 124:3) “when their wrath was kindled (בחרות)”. This is its literal meaning which fits in with the sense, for חצות is not a noun, being another form of חֵצִי (when the meaning would be about midnight I will go out etc.”, for this does not fit in with the sense, since God would certainly have stated exactly when He would do this). But our Rabbis took it in this sense and explained it as meaning “about the middle of the night”, and they asserted that Moses said כחצות “about midnight”, which implies near to it — either just before it or just after it, and he did not say בחצות “at midnight” (as God had bidden him say) because he feared lest Pharaoh’s astrologers might make a mistake as regards the time when the slaughter of the firstborn actually took place, thinking that it was a little earlier or later than midnight, and would say, in consequence of this error, “Moses is a liar!” (cf. Berakhot 4a).

Hashem specifically commands Eliyahu HaNavi to orchestrate the events at Har HaCarmel. Indeed, at Har HaCarmel, Eliyahu HaNavi proclaims to Hashem that “UBiDevarecha Asiti Eit Kol HaDevarim Ha’Eileh,” “it is by Your word that I have done all these things” (Melachim I 18:36).

ויגש אברהם AND ABRAHAM DREW NEAR — We find the verb ננש “to come near” used in the sense of coming near to wage war — (2 Samuel 10:13) “So Joab … drew near unto the battle”; — of coming near to persuade by entreaty — (44:18) “And Judah came near to him [and said, Oh, my lord]” — and of coming near to pray — (1 Kings 18:36) “And Elijah the prophet came near [and said, O Lord, God of Abraham etc.]” Abraham employed all these methods — to fight, by speaking stern words, and to persuade by entreaty, and to pray (Genesis Rabbah 49:8).