21. σὺ οὖν μὴ πεισθῇς αὐτοῖς, do not thou therefore yield to them. The οὖν refers to the idea of a scheme in which the chief captain was to be made use of; this has only been suggested in the previous verse, not directly stated.
ἀνεθεμάτισαν ἑαυτούς, they have bound themselves under a curse. Cf. Act 23:12 above.
προσδεχόμενοι τὴν ἀπὸ σοῦ ἐπαγγελίαν, looking for the promise from thee, i.e. which they are coming to try and induce thee to make to them.