A.T. Robertson Commentary Revelation 13:10

"If any man [is] for captivity, into captivity he goeth: if any man shall kill with the sword, with the sword must he be killed. Here is the patience and the faith of the saints." — Revelation 13:10 (ASV)

If any man is for captivity (ε τις εις αιχμαλωσιαν). Condition of first class, but with no copula (εστιν) expressed. For αιχμαλωσιαν (from αιχμαλωτος captive) see Eph 4:8, only other N.T. example. Apparently John means this as a warning to the Christians not to resist force with force, but to accept captivity as he had done as a means of grace. Cf. Jeremiah 15:2. The text is not certain, however.

If any man shall kill with the sword (ε τις εν μαχαιρη αποκτενε). First-class condition with future active of αποκτεινω, not future passive, for it is a picture of the persecutor drawn here like that by Jesus in Mt 26:52.

Must he be killed (δε αυτον εν μαχαιρη αποκτανθηνα). First aorist passive infinitive of αποκτεινω. The inevitable conclusion (δε) of such conduct. The killer is killed.

Here (ωδε). In this attitude of submission to the inevitable. For ωδε see 13:18; 14:12; 17:9. "Faith" (πιστις) here is more like faithfulness, fidelity.