{He wavered not through unbelief} (ou diekrith(8820)t(8869)
apisti(8369)). First aorist passive indicative of old and common
verb diakrin(935c), to separate, to distinguish between, to decide
between, to desert, to dispute, to be divided in one's own mind.
This last sense occurs here as in  Mt 21:22  Mr 11:23  Ro 14:23  Jas 1:6 . "He was not divided in his mind by unbelief"
(instrumental case). {Waxed strong through faith} (enedunam(9374)h(880a)t(8869) pistei). First aorist passive again of endunamo(935c), late
word to empower, to put power in, in LXX and Paul and  Ac 9:22 .