ει conditional
ei  i: if, whether, that, etc. -- forasmuch as, if, that, (al-)though, whether.
απιστουμεν verb - present active indicative - first person
apisteo  ap-is-teh'-o: to be unbelieving, i.e. (transitively) disbelieve, or (by implication) disobey -- believe not.
εκεινος demonstrative pronoun - nominative singular masculine
ekeinos  ek-i'-nos: that one (or (neuter) thing); often intensified by the article prefixed -- he, it, the other (same), selfsame, that (same, very), their, them, they, this, those.
πιστος adjective - nominative singular masculine
pistos  pis-tos': objectively, trustworthy; subjectively, trustful -- believe(-ing, -r), faithful(-ly), sure, true.
μενει verb - present active indicative - third person singular
meno  men'-o: to stay (in a given place, state, relation or expectancy) -- abide, continue, dwell, endure, be present, remain, stand, tarry (for), thine own.
αρνησασθαι verb - aorist middle deponent middle or passive deponent
arneomai  ar-neh'-om-ahee: to contradict, i.e. disavow, reject, abnegate -- deny, refuse.
εαυτον reflexive pronoun - third person accusative singular masculine
heautou  heh-ow-too': him-(her-, it-, them-, also (in conjunction with the personal pronoun of the other persons) my-, thy-, our-, your-) self (selves), etc.
ου particle - nominative
ou  oo: no or not -- + long, nay, neither, never, no (man), none, (can-)not, + nothing, + special, un(-worthy), when, + without, + yet but.
δυναται verb - present middle or passive deponent indicative - third person singular
dunamai  doo'-nam-ahee: to be able or possible -- be able, can (do, + -not), could, may, might, be possible, be of power.