To whom also (hois kai). He chose them and then also manifested himself to these very same men that they might have personal witness to give.
Shewed himself alive (parestēsen heauton zōnta). To the disciples the first Sunday evening (Mar 16:14; Luk 24:36-43; Joh 20:19-25), the second Sunday evening (Joh 20:26-29), at the Sea of Tiberias (John 21:1-23), on the mountain in Galilee (Mat 28:16-20; Mar 16:15-18; 1Co 15:6), to the disciples in Jerusalem and Olivet (Luk 24:44-53; Mar 16:19.; Act 1:1-11). Luke uses this verb paristēmi 13 times in the Acts both transitively and intransitively. It is rendered by various English words (present, furnish, provide, assist, commend). The early disciples including Paul never doubted the fact of the Resurrection, once they were convinced by personal experience. At first some doubted like Thomas (Mar 16:14; Luk 24:41; Joh 20:24.; Mat 28:17). But after that they never wavered in their testimony to their own experience with the Risen Christ, “whereof we are witnesses” Peter said (Act 3:15). They doubted at first, that we may believe, but at last they risked life itself in defence of this firm faith.
After his passion (meta to pathein auton). Neat Greek idiom, meta with the articular infinitive (second aorist active of paschō) and the accusative of general reference, “after the suffering as to him.” For pathein used absolutely of Christ’s suffering see also Act 17:3; Act 26:23.
By many proofs (en pollois tekmēriois). Literally, “in many proofs.” Tekmērion is only here in the N.T., though an old and common word in ancient Greek and occurring in the Koinéš (papyri, etc.). The verb tekmairō, to prove by sure signs, is from tekmar, a sign. Luke does not hesitate to apply the definite word “proofs” to the evidence for the Resurrection of Christ after full investigation on the part of this scientific historian. Aristotle makes a distinction between tekmērion (proof) and sēmeion (sign) as does Galen the medical writer.
Appearing (optanomenos). Present middle participle from late verb optanō, late Koinéš verb from root optō seen in opsomai, ōphthēn. In lxx, papyri of second century b.c. (Deissmann, Light from the Ancient East, p. 83). Only here in the N.T. For optasia for vision, see note on Act 26:19; Luk 1:22; Luk 24:23.
By the space of forty days (di' hēmerōn tesserakonta). At intervals (dia, between) during the forty days, ten appearances being known to us. Jesus was not with them continually now in bodily presence. The period of forty days is given here alone. The Ascension was thus ten days before Pentecost when the Holy Spirit came. Moses was in the mount forty days (Exo 24:18) and Jesus fasted forty days (Mat 4:2). In the Gospel of Luke 24 this separation of forty days between the Resurrection and the Ascension is not drawn.
The things concerning the Kingdom of God (ta peri tēs basileias tou theou). This phrase appears 33 times in Luke’s Gospel, 15 times in Mark, 4 times in Matthew who elsewhere has “the kingdom of heaven,” once in John, and 6 times in Acts. No essential distinction is to be drawn between the two for the Jews often used “heaven” rather than “God” to avoid using the Tetragrammaton. But it is noticeable how the word kingdom drops out of Acts. Other words like gospel (euaggelion) take the place of “kingdom.” Jesus was fond of the word “kingdom” and Luke is fond of the idiom “the things concerning” (ta peri). Certainly with Jesus the term “kingdom” applies to the present and the future and covers so much that it is not strange that the disciples with their notions of a political Messianic kingdom (Act 1:6) were slow to comprehend the spiritual nature of the reign of God.