On the evening after his resurrection, Jesus “breathed on them and said to them, ‘Receive the Holy Spirit.'” (Jn 20:22). How, then, is it possible to become “filled with the Holy Spirit” seven weeks later on Pentecost (Acts 2:1-4) if the disciples had already received the Holy Spirit?
According to John the Baptizer, “a person cannot receive even one thing unless it is given him from heaven” (Jn 3:27). Therefore, Jesus’s power and infilling of the Holy Spirit would seem to have come upon him at the Jordan, driven him to the wilderness, and grown “like a mustard seed.” Baptism and infilling of the Holy Spirit indeed seem to be connected: “be baptized, every one of you, in the name of Jesus Christ for the forgiveness of your sins. And you will receive the gift of the Holy Spirit.” (Acts 2:38)
The first truth that emerges is that the indwelling of the Holy Spirit is not necessarily substantiated by outward manifestations. The second truth is that Jesus imparted to his disciples what had been imparted to him when he was first water-baptized (Jn 1:32-33, Mk 1:10, Lk 3:22, Mt 3:16).
On the day of Pentecost the disciples were gathered together when there was a sensory phenomenon of sight and sound, and they began speaking in unknown tongues (Acts 2:4). Interestingly enough, the text does not say that they spoke in tongues for the first time, only that they began speaking in tongues (perhaps indicating they were so overpowered by the Holy Spirit that their customary language failed them). If they were speaking languages that could be identified then the text would say that they began speaking in Phoenician, Sanskrit, etc. Some outside witnesses claimed to “hear them speak in his own language” (Acts 2:6). Other witnesses just heard babbling and accused the disciples of drunkenness (Acts 2:13). So the same utterances were simultaneously interpreted in distinct ways. Thus it was the anointing conveyed within the utterances which struck the spirits and minds of the first cohort of witnesses to perceive the message as intelligible thought in the language(s) which the hearer(s) knew. We are left to conclude that the other cohort was spiritually deaf. This auditory manifestation follows the predicate of John 12:28-30 in which some perceived thunder, some heard an indistinct angel, some understood actual words. Thus it is seen that human subjects perceive God’s oracles according to their spiritual receptiveness (some perceived thunder, some heard an indistinct angel, some understood actual words).
One takeaway here is that “speaking in tongues” is not the sole proof of the indwelling of the Holy Spirit. One can possess the Holy Spirit without speaking in tongues which probably flows from a separate (dry) baptism. Uttering humanly unintelligible sounds simply means that one’s prayer transcends the limitations of human speech, that the declarations and supplications of the Holy Spirit are just too complex to be reduced to a finite vocabulary and syntax (1 Cor 14:14). Another takeaway is that those utterances are concealed from the Agents of Hell (whether human or demonic) who have not the ability to understand what they do not possess because it has not been given to them from heaven.
In sum, one must first receive the Holy Spirit through water baptism to also receive the spiritual gift of tongues, but one may receive the Holy Spirit and still not speak in unknown spiritual tongues.