Proof of Receiving God's Holy Spirit
The primary evidence of receiving the Promise of the Holy Spirit that the Father has shown us in His revelation is that of speaking in a new language by the inspiration of the Spirit.
Christ Jesus prophesied of this experience of speaking in new languages in His name and that it would follow His believers:
17These signs will accompany those who believe: in my name they will cast out demons; they will speak with new languages; Mark 16:17
This ability is not something natural, or the mere learning of a new language through education. It is the supernatural ability that the Holy Spirit supplies to the child of God who has been baptized into Him. The Spirit gives the believer the new words of the language of His choosing, which speak the perfect will of the Father.
1Now when the day of Pentecost had come, they were all with one accord in one place. 2Suddenly there came from the sky a sound like the rushing of a mighty wind, and it filled all the house where they were sitting. 3Tongues like fire appeared and were distributed to them, and one sat on each of them. 4They were all filled with the Holy Spirit, and began to speak with other languages, as the Spirit gave them the ability to speak. Acts 2:1-4
In this first recording of the Promise being received by God's people, we see its fruit was to confirm the work of the Father in His Son (Acts 2:11). This testimony given through the languages spoken by the Spirit through the disciples led to the apostle Peter leading over 3000 people into the Kingdom of Yahweh through trust in His Son.
Peter connected this experience of speaking in languages to the prophecy of Joel made numerous centuries before, through the inspiration of the Holy Spirit.
12They were all amazed, and were perplexed, saying to one another, “What does this mean?” 13Others, mocking, said, “They are filled with new wine.” 14But Peter, standing up with the eleven, lifted up his voice, and spoke out to them, “You men of Judea, and all you who dwell at Jerusalem, let this be known to you, and listen to my words. 15For these aren’t drunken, as you suppose, seeing it is only the third hour of the day. 16But this is what has been spoken through the prophet Joel: 17‘It will be in the last days, says God, that I will pour out my Spirit on all flesh. Your sons and your daughters will prophesy. Your young men will see visions. Your old men will dream dreams. 18Yes, and on my servants and on my handmaidens in those days, I will pour out my Spirit, and they will prophesy. Acts 2:12-18
32This Jesus God raised up, to which we all are witnesses. 33Being therefore exalted by the right hand of God, and having received from the Father the promise of the Holy Spirit, he has poured out this, which you now see and hear. Acts 2:32,33
This same fruit of praise of God in a new language continued to be Yahweh's proof to His people of the infilling of the Holy Spirit. Not many years later, the first time that newly believing, non-proselyte Gentiles (i.e., those who had not previously converted to Judaism, observing the Law of Moses) received the Holy Spirit, the same evidence followed:
45They of the circumcision who believed were amazed, as many as came with Peter, because the gift of the Holy Spirit was also poured out on the Gentiles. 46For they heard them speaking in other languages and magnifying God. Then Peter answered, 47“Can anyone forbid these people from being baptized with water? They have received the Holy Spirit just like us.” Acts 10:45-47
The Jewish believers had come to recognize this as the proof that the Spirit had fallen upon a believer (Acts 15:8-9).
The Progression of Belief to Infilling
The apostle Paul used this evidence when preaching the Gospel to non-Jews. The Promise of the Father was the Holy Spirit given to those who trusted in God's Christ, Jesus:
1While Apollos was at Corinth, Paul, having passed through the upper country, came to Ephesus, and found certain disciples. 2He said to them, “Did you receive the Holy Spirit when you believed?” They said to him, “No, we haven’t even heard that there is a Holy Spirit.” Acts 19:1,2
It is necessary to be sure that a person has entered covenant with Yahweh through His Son, and does not remain under the Old Covenant, or remain yet in total ignorance of God. The answer of these disciples was very telling. They had only had the message of John the Baptizer preached to them: to expect the coming of Christ, the Son of God. But they had yet to realize who He was and that He had already come.
3He said, “Into what then were you baptized?” They said, “Into John’s baptism.” Acts 19:3
Paul then explains the point of John's prepartion ministry, to clear a path for Yahweh in the flesh, the Lord Jesus Christ.
4Paul said, “John indeed baptized with the baptism of repentance, saying to the people that they should believe in the one who would come after him, that is, in Jesus.” Acts 19:4
They had been prepared by the ministry of God's final prophet of the Old Covenant, John, who had operated by the spirit of Elijah. Now they were ready to receive God's gift of eternal life through trusting in His only Son:
5When they heard this, they were baptized in the name of the Lord Jesus. Acts 19:5
Following this, the apostle did not leave them unconfirmed in their new faith, but immediately led them into the Promise of the Father to His called people. Now that they had come to be new creations in Christ they were eligible to receive the Promise of their Father:
6When Paul had laid his hands on them, the Holy Spirit came on them, and they spoke with other languages and prophesied. Acts 19:6
Again, Yahweh gave proof of their experience by His Spirit giving them words of a new language with which to praise and worship Him, as well as leading them to prophesy of His greatness in their native language.
Fulfillment of Prophecy
In his first letter to the Corinthian Assembly, Paul sums it all up, connecting this experience of speaking in other languages after having the Holy Spirit fall, to the "sign" spoken of by Isaiah. Speaking in other languages, after being baptized into the Holy Spirit, is the sign to the unbelievers spoken of by Isaiah! It accompanies being filled with the Holy Spirit, and is promised to all people, both small and great, everywhere, and forever. It also is the refreshing, and the mean to rest ourselves, as we will see later. Praise the Living God!
11But he will speak to this nation with stammering lips and in another language; 12to whom he said, “This is the resting place. Give rest to weary”; and “This is the refreshing”; yet they would not hear. Isaiah 28:11,12
22Therefore other languages are for a sign, not to those who believe, but to the unbelieving; but prophesying is for a sign, not to the unbelieving, but to those who believe. 1 Corinthians 14:22
This experience of speaking in a new language as the Holy Spirit is giving you the ability, is a biblical sign of both your belief in Christ, and your redemption from believing; and also that you have received the promise of the Father, the gift of the Holy Spirit! There is yet much more to this wonderful gift! Thank your Father in heaven for this wonderful blessing, and Jesus for giving you the ability to receive it, through His obedience!