The house wherewith I have war - Necho viewed Babylon as the successor and representative of Assyria - the hereditary enemy of Egypt - and he means that he is merely continuing an old hostility with which Josiah has nothing to do. No doubt the Assyrian and Egyptian armies had often passed up and down Syria by the coast route, without approaching Jerusalem, or even touching the soil of Judaea.
God commanded me to make haste: forbear thee from meddling with God - These are remarkable words in the mouth of a pagan; but ancient inscriptions show that the Egyptian kings, in a certain sense, acknowledged a single supreme god, and considered their actions to be inspired by him. (e. g. The god Tum (compare) the name of his city, Pithom, Exodus 1:11 note) was worshipped as ankh, “the living One” (compare “Yahweh”)). Hence, Necho merely expressed himself as Egyptian kings were in the habit of doing.