{Because I have you in my heart} (dia to echein me en t(8869)
kardi(8369) humas). Or "because you hold me in your heart."
Literally, "because of the holding me (or you) in the heart as to
you (or me)." One accusative is the object of the infinitive
echein, the other is the accusative of general reference. There
is no way to decide which is the idea meant except to say that
love begets love. The pastor who, like Paul, holds his people in
his heart will find them holding him in their hearts. {In the
defence} (en t(8869) apologi(8369)). Old word (our word apology, but
not our idea of apologizing), in the original sense in  Ac 22:1  25:16 . So also in verse  16  below. {Confirmation}
(ebai(9373)ei). Old word from ebaio(935c) (ebaios, bain(935c)), to
make stable. In N.T. only here and  Heb 6:16  about oath.
{Partakers with me of grace} (sugkoin(936e)ous mou t(8873) charitos).
Literally, "my co-sharers in grace" (objective genitive). "Grace
prompted them to alleviate his imprisonment, to cooperate with
him in defending and propagating the gospel, and to suffer for
its sake" (Vincent, _Int. Crit. Comm_.).