2 occurrences across the corpus

Apostolic Fathers

Ignatius to Polycarp 2:14

Please him under whom ye war, and from whom ye receive your wages. Let none of you be found a deserter; but let your baptism remain, as your arms; your faith, as your helmet; your charity, as your spear; your patience, as your whole armour.

NT Apocrypha/Pseudepigrapha

The Martyrdom of the Holy Apostle Paul 4:4

Then they beseeching him said: We entreat thee, help us, and we will let thee go. But he answered and said: I am not a deserter of Christ, but a lawful soldier of the living God. If I had known that I should die, O Longus and Cestus, I would have done it; but seeing that I live unto God and love myself, I go unto the Lord, to come with him in the glory of his Father.