speaking the truth - Translate, “holding the truth”; “following the truth”; opposed to “error” or “deceit” (Eph 4:14).
in love - “Truth” is never to be sacrificed to so-called “charity”; yet it is to be maintained in charity. Truth in word and act, love in manner and spirit, are the Christian’s rule (compare Eph 4:21, Eph 4:24).
grow up - from the state of “children” to that of “full-grown men.” There is growth only in the spiritually alive, not in the dead.
into him - so as to be more and more incorporated with Him, and become one with Him.