He supposed (enomizen). Imperfect active of nomizō. He was supposing, Stephen explains, when he smote the Egyptian.
That his brethren understood (sunienai tous adelphous). Present active infinitive of suniēmi, to send (put) together, to grasp, to comprehend, in indirect discourse with the accusative of general reference.
By his hand was giving them deliverance (dia cheiros autou didōsin sotērian autois). Picturesque use of “hand” as in Act 2:23, present active indicative of didōmi retained in indirect discourse after imperfect enomizen. But they understood not (hoi de ou sunēkan). Page notes “the rhetorical power of these words” from Stephen. Sunēkan (first aorist indicative, k aorist) refers to sunienai just before.