Jesus said in John 3:5, 'Most assuredly, I say to you, unless one is born of water and the Spirit, he cannot enter the kingdom of God.' In John 4:14 He said, 'Whoever drinks of the water that I shall give him will never thirst. But the water that I shall give him will become in him a fountain of water springing up into everlasting life.' In John 7:37 He cried out, 'If anyone thirsts, let him come to Me and drink. He who believes in Me, as the Scripture has said, out of his heart will flow rivers of living water.' The Gospel writer then explained, 'But this He spoke concerning the Spirit, whom those believing in Him would receive; for the Holy Spirit was not yet given, because Jesus was not yet glorified' (v.30). When we put all these verses together, we can see that the Spirit is the living water that springs up into everlasting life. The question then is: how does one know for a certainty that he has received the Spirit?
Just before His ascension, Jesus told his disciples, 'John truly baptized with water, but you shall be baptized with the Holy Spirit not many days from now: (Acts 1:5). A few verses later we read of the outpouring of the Spirit. The Bible says, 'And they were all filled with the Holy Spirit and began to speak with other tongues, as the Spirit gave them utterance' (Acts 2:4). In Acts 10:45-46 we read, 'The gift of the Holy Spirit had been poured out on the Gentiles also. For they heard them speak with tongues and magnify God.' And in Acts 19:5-6 we read, 'When they heard this, they were baptized in the name of the Lord Jesus. And when Paul had laid hands on them, the Holy Spirit came upon them, and they spoke with tongues and prophesied.'
So, to answer your question, we would say that it is necessary to receive the gift of the Spirit and that the biblical way of knowing you have received the Spirit is speaking in tongues. This is, of course, not the only thing necessary, which is why we would not say that you have to speak in tongues to go to heaven. This implies that everyone who speaks in tongues will go to heaven and this is not the case.