John Gill Commentary 1 Kings 18:5

"And Ahab said unto Obadiah, Go through the land, unto all the fountains of water, and unto all the brooks: peradventure we may find grass and save the horses and mules alive, that we lose not all the beasts." — 1 Kings 18:5 (ASV)

And Ahab said to Obadiah, go into the land, to all
fountains of water, and to all brooks
To observe in what condition they were, and the places adjoining to them, the meadows and valleys: perhaps we may find grass to save the horses and mules alive ;
particularly those which belonged to the king's stables, to find provisions for which it was found difficult: that we lose not all the beasts ;
many of them, doubtless, were lost through the drought already, and there was great danger of the rest, and so, in time, of there being none to procreate and preserve their species, and to prevent which Ahab proposed to take this method.