acts 1:3 To whom also he shewed himself alive after his passion by many infallible proofs, being seen of them forty days, and speaking of the things pertaining to the kingdom of God: - Free Bible Online

      3-5. showed himself alive--As the author is about to tell us that "the resurrection of the Lord Jesus" was the great burden of apostolic preaching, so the subject is here filly introduced by an allusion to the primary evidence on which that great fact rests, the repeated and undeniable manifestations of Himself in the body to the assembled disciples, who, instead of being predisposed to believe it, had to be overpowered by the resistless evidence of their own senses, and were slow of yielding even to this (Mr 16:14).
      after his passion--or, suffering. This primary sense of the word "passion" has fallen into disuse; but it is nobly consecrated in the phraseology of the Church to express the Redeemer's final endurances.
      seen of them forty days--This important specification of time occurs here only.
      speaking of--rather "speaking."
      the things pertaining to the kingdom of God--till now only in germ, but soon to take visible form; the earliest and the latest burden of His teaching on earth.

JFB.