A.T. Robertson Commentary Luke 18:7

"And shall not God avenge his elect, that cry to him day and night, and [yet] he is longsuffering over them?" — Luke 18:7 (ASV)

And he is longsuffering (μακροθυμε). This present active indicative comes in awkwardly after the aorist subjunctive ποιηση after ου μη, but this part of the question is positive. Probably κα here means "and yet" as so often (John 9:30; 16:32, etc.). God delays taking vengeance on behalf of his people, not through indifference, but through patient forbearance.