Acts 9:16 - Ellicott's Commentary On The Whole Bible

For I will shew him how great things he must suffer... — The words are spoken as by One who knows “what is in man” (John 2:25), their secret motives, and springs of action. With characters of a lower type, the prospect of what they will have to suffer in any enterprise tends to deter them from embarking on it. With such a one as Saul of Tarsus, now repenting of the sufferings he had inflicted on others, that prospect would be welcome as enabling him, so far as that was possible, if not to atone for the past, at least to manifest fruits worthy of his repentance.