{I will shew} (hupodeix(935c)). Beforehand as a warning as in
 Lu 3:7  and from time to time. {He must suffer} (dei auton
pathein). Constative aorist active infinitive (pathein, from
pasch(935c)) covering the whole career of Saul. Suffering is one
element in the call that Saul receives. He will learn "how many
things" (hosa) are included in this list by degrees and by
experience. A glance at  2Co 10-12  will show one the fulfilment
of this prophecy. But it was the "gift" of Christ to Paul to go
on suffering (paschein, present infinitive,  Php 1:39 ).