Abstain from every form of evil (apo pantos eidous ponērou apechesthe). Present middle (direct) imperative of aṗechō (contrast with kaṫechō) and preposition apo repeated with ablative as in 1Th 4:3. Note use of ponērou here for evil without the article, common enough idiom. Eidos (from eidon) naturally means look or appearance as in Luk 3:23; Luk 9:29; Joh 5:37; 2Co 5:7. But, if so taken, it is not semblance as opposed to reality (Milligan). The papyri give several examples of eidos in the sense of class or kind and that idea suits best here. Evil had a way of showing itself even in the spiritual gifts including prophecy.