{He that doubteth} (ho diakrinomenos). Present middle
participle of diakrin(935c), to judge between (dia), to hesitate.
See  Jas 1:6f.  for this same picture of the double-minded man.
Cf.  Ro 4:20  Mr 11:23 . {Is condemned} (katakekritai). Perfect
passive indicative of katakrin(935c) (note kata-), "stands
condemned." {If he eat} (ean phag(8869)). Third class condition,
ean and second aorist active subjunctive. If in spite of his
doubt, he eat. {Whatsoever is not of faith is sin} (pan ho ouk
ek piste(9373) hamartia estin). {Faith} (pistis) here is
subjective, one's strong conviction in the light of his relation
to Christ and his enlightened conscience. To go against this
combination is sin beyond a doubt. Some MSS. (A L etc.) put the
doxology here which most place in  16:25-27 . But they all give
chapters 15 and 16. Some have supposed that the Epistle
originally ended here, but that is pure speculation. Some even
suggest two editions of the Epistle. But chapter 15 goes right on
with the topic discussed in chapter 14.