פירוש על מלכים א 18:36

And at Your word have I done. That I sacrificed on a private altar during the period of the prohibition of [offering sacrifices on] private altars.¹⁹This verse implies that God commanded Eliyahu to offer the sacrifice on Mount Carmel even though private altars were not permitted once the Beis Hamikdosh had been built. See footnote on v. 30 above and Tosafos in Maseches Sanhedrin 89b.