True (gnēsiōi). Legitimate, not spurious. Old word from ginomai, but Pauline only in N.T. (Phi 4:3; 2Co 8:8; Tit 1:4). In Phi 2:20 the adverb gnēsiōs occurs and of Timothy again.
Christ Jesus (Christou Iēsou). So twice already in 1Ti 1:1 and as usual in the later Epistles (Col 1:1; Eph 1:1).