Commentaire sur Rois 1 18:30

And he repaired the altar of Adonoy that had been broken down. He built an altar⁷A ‘ח’ and an ‘ע’ are both guttural letters and are therefore interchangeable. and reminded Yisroel that God’s altar should enter their thoughts and should be oft mentioned, for it was torn down and destroyed, and its name and its mention had ceased from the mouth of all the ten tribes. Thus I heard is its plain interpretation.⁸Although once the Beis Hamikdosh was built private altars were not permitted, however, extraordinary circumstances allow for the suspension of certain laws in cases of dire necessity, such as this. See Maseches Sanhedrin 89b and Tosafos there. Also see footnote on v. 36 below. And its Midrashic interpretation I heard, is that Shaul built an altar on Mount Carmel, and that is what it states, “Shaul came to Carmel, and is setting up a place for himself,”⁹Alternatively, as a result of the miracle on Mount Carmel, many people repented and went to Yerusholayim to offer sacrifices in the Beis Hamikdosh. Thus he reactivated [וירפא] the altar which had been dormant [ההרוס].—Radak and there it states, “and he erected an altar there.”¹⁰I Shmuel 15:12. But the kings of Yisroel tore down all the altars and high places in their land that were made in the Name of Heaven, and Eliyahu built this altar of Shaul that had been torn down.

And he healed By way of borrowing [from its original meaning], it used the term, healing, [to mean] building a destroyed building. And likewise (Nehemiah 4:1), "that healing had come to the walls of Jerusalem"; and likewise (I Chronicles 11:8), "and Yoav resuscitated the rest of the city."