Jamieson, Fausset and Brown on 1 Timothy 6:14

14. keep this commandment--Greek, "the commandment," that is, the Gospel rule of life (1Ti 1:5; Joh 13:34; 2Pe 2:21; 3:2).

without spot, unrebukeable--agreeing with "thou." Keep the commandment and so be without spot," &c. "Pure" (1Ti 5:22; Ep 5:27; Jas 1:27; 2Pe 3:14).

until the appearing of ... Christ--His coming in person (2Th 2:8; Tit 2:13). Believers then used in their practice to set before themselves the day of Christ as near at hand; we, the hour of death [Bengel]. The fact has in all ages of the Church been certain, the time as uncertain to Paul, as it is to us; hence, 1Ti 6:15, he says, "in His times": the Church's true attitude is that of continual expectation of her Lord's return (1Co 1:8; Php 1:6, 10).