Acts 1:4-8 Baptized Witnesses.
It was while He visited with them, with His resurrection body, that Jesus repeated this promise of the coming of the Spirit, who would be sent by the Father (v. 4 Cf. Jn. 14:16, 26; 15:26). It was the same promise with which Luke ended volume one of his history. It was the gospel promise which led them to gather as they did (24:49). What they would experience would be a baptism, with the Spirit (v. 5). It would be a work of the Father and Son together, as John the Baptist, by the same Spirit, predicted (Cf. Mt. 3:11; Joel 2:28). “John’s water baptism of repentance (Mark 1:4) pointed forward to the messianic baptism with the Holy Spirit and fire (Luke 3:16)” (NGSB p. 1710).
However, the focus of the disciples was still on the restoration of the kingdom of Israel, and not the messianic kingdom which it was intended to foreshadow (v. 6). He does not re-engage in this discussion, but rather reminds them that only the Father knows the exact time of His return (v. 7 Cf. Mt. 24:36; I Th. 5:1-2). What He does emphasize is the work that He was calling them to in His kingdom. The point of the sending of the Holy Spirit was that He would give them the power they needed to fulfill the kingdom work of being His witnesses (v. 8). Even though the revelatory gifts have ceased, we also still need His presence, that we might have the power to carry on this witness.