Problem: In Acts, the apostles are told to wait until Pentecost before they receive the Holy Spirit (Acts 1:4–8; cf. 2:1–2). Yet even before His crucifixion Jesus breathed on His disciples and said, “Receive the Holy Spirit” (John 20:22). Didn’t they receive the Holy Spirit at this point and not later at Pentecost?
Solution: First of all, the John passage is a difficult one, with no direct parallels, and it is hard to know exactly what it means. And like all obscure passages, one should not base any major teaching on it.
Second, some scholars believe that the imperative “receive” is intended to denote the future “you will receive.” If so, then there is no conflict.
Third, even if Jesus meant them to receive the Holy Spirit at that moment (in John 20:22), it was apparently in a different sense. Here the Spirit is given “to forgive the sins” (v. 23). But in Acts 1:8 the Spirit was to be given to provide “power … [to] be witnesses” for Him to the “end of the earth.”
Fourth, the promise of the Spirit in John was for His indwelling the believer (cf. John 14:16), not for His being baptized by the Holy Spirit (Acts 1:5; cf. 1 Cor. 12:13), which is a different act of the Holy Spirit. In this sense, then, there is no conflict between the two passages, since they speak of different activities of the Spirit which came at different times.