For I am already being poured out like a drink offering, and the time has come for my departure. 2 Timothy 4:6 [NIV]
"Twice Paul refers to himself as a “drink offering,” here and in Philippians 2:17. In the Old Testament, a drink offering was a small portion of wine poured around the base of the altar of the animal sacrifice. It was a small thing compared to the carcass of the animal that was being sacrificed, but it expressed the worshiper’s thankfulness to God.
Paul sees himself in the same way, particularly as he knows his life is ending. His service to God is an insignificant thing in comparison to the sacrifice of Christ, but it is freely offered to God in gratitude."
(General Editor Jean E. Syswerda, NIV Women of Faith Study Bible, Zondervan Publishing House, Grand Rapids, Mischigan, 2001, pg 1980)