Isaiah 57:5

Enflaming yourselves. — The best illustration of the phrase is found in the real or supposed derivation of “fanatic” as meaning one who is circa fana calefactus. No word could better describe the orgiastic excitement of heathen rites. For “with idols read among the terebinths, which were prominent, with other trees, in the groves dedicated to idol-worship (Hosea 4:13; Ezekiel 6:13).

Under every green tree is almost a stereotyped formula in this connection (Deuteronomy 12:2; 1 Kings 14:23; Jeremiah 2:20), the tree itself becoming a direct object of the cultus.

Slaying the children in the valleys... — This had been done by Ahaz (2 Chronicles 28:3). It was perfectly natural that it should be done by Manasseh. There is not the slightest trace of the revival of the practice among the exiles in Babylon or after their return. The scenery described — the torrent-stream, the clefts of the rock — belongs distinctively to Palestine.