Jamieson, Fausset & Brown

Greek, "For I am already being offered"; literally, as a libation; appropriate to the shedding of his blood. Every sacrifice began with an initiatory libation on the victim's head (compare Note, see on Phi 2:17). A motive to stimulate Timothy to faithfulness--the departure and final blessedness of Paul; it is the end that crowns the work [BENGEL]. As the time of his departure was indicated to Peter, so to Paul (Pe2 1:14). my departure--literally, "loosing anchor" (see on Phi 1:23). Dissolution.