Do ye look on things after the outward appearance? — The Greek sentence may be taken either as interrogative, imperative, or indicative. The latter “ye look on things...” gives the most satisfactory meaning, as pressing home the charge on which he proceeds to dwell. He has, of course, the party of resistance in his thoughts, but he writes to the whole community, as influenced — some more and some less — by the tendency to attach undue weight to the outward accidents of those who claimed their allegiance rather than to that which was of the essence of all true Apostolic ministry.
If any man trust to himself that he is Christ’s... — There cannot be the shadow of a doubt that the words refer to those whose watchword was “I am of Christ” (see Note on 1 Corinthians 1:12), who laid claim to some special connection with Him, either as having been His personal disciples, or, at least, as having seen and known Him. In answer to that claim, with a half-ironical emphasis on “let him think,” or “let him reckon” (comp. 2 Corinthians 10:2; 2 Corinthians 10:5), he asserts that he is as truly His — i.e., connected with Him, chosen by Him — as they were.