a phrase combining
G3588 with the present participle and imperfect of
G1510 and the present participle of
G2064 by means of
G2532; the one being and the one that was and the one coming, i.e. the Eternal, as a divine epithet of Christ:--which art (is, was), and (which) wast (is, was), and art (is) to come (shalt be).