The Spirit is a gift, received through faith in Jesus Christ, not earned by works or by feelings. When you trust Christ, you are sealed with the promised Holy Spirit; and as you walk with Him, you are filled again and again.
Not a summary of these passages: the passages themselves. Read them, then come back to the study below.
The study
What the Scripture says
1
The Spirit is received through faith, not works
Paul's question to the Galatians is the key: 'Did you receive the Spirit by the works of the law, or by hearing of faith?' The Spirit comes by believing the gospel, the same way salvation itself comes.
I just want to learn this from you. Did you receive the Spirit by the works of the law, or by hearing of faith?
in whom you also, having heard the word of the truth, the Good News of your salvation—in whom, having also believed, you were sealed with the Holy Spirit of promise,
He is the gift promised to all who repent and believe
Peter's answer to 'What must we do?' was: repent and be baptized in the name of Jesus Christ for the forgiveness of sins: 'and you will receive the gift of the Holy Spirit.' The promise is not for a select few; it is for everyone the Lord calls.
Peter said to them, “Repent, and be baptized, every one of you, in the name of Jesus Christ for the forgiveness of sins, and you will receive the gift of the Holy Spirit. For the promise is to you, and to your children, and to all who are far off, even as many as the Lord our God will call to himself.”
Paul writes that having believed, you were sealed with the Holy Spirit of promise: the seal, the down payment of the inheritance. Jesus described the Spirit as rivers of living water flowing from within the believer.
in whom you also, having heard the word of the truth, the Good News of your salvation—in whom, having also believed, you were sealed with the Holy Spirit of promise, who is a pledge of our inheritance, to the redemption of God’s own possession, to the praise of his glory.
Now on the last and greatest day of the feast, Jesus stood and cried out, “If anyone is thirsty, let him come to me and drink! He who believes in me, as the Scripture has said, from within him will flow rivers of living water.” But he said this about the Spirit, which those believing in him were to receive. For the Holy Spirit was not yet given, because Jesus wasn’t yet glorified.
The Spirit of adoption replaces the spirit of fear. Through Him we call God our Father with the intimate confidence of a child, and He Himself testifies with our spirit that we are God's children.
For as many as are led by the Spirit of God, these are children of God. For you didn’t receive the spirit of bondage again to fear, but you received the Spirit of adoption, by whom we cry, “Abba! Father!” The Spirit himself testifies with our spirit that we are children of God;
But you are not in the flesh but in the Spirit, if it is so that the Spirit of God dwells in you. But if any man doesn’t have the Spirit of Christ, he is not his.
Receiving the Spirit is the beginning; being filled is the ongoing life. We are commanded to be filled with the Spirit, and to walk by Him, and not to grieve Him. The filling is not one dramatic moment, but a continual surrender.
Don’t be drunken with wine, in which is dissipation, but be filled with the Spirit,
Peter said to them, “Repent, and be baptized, every one of you, in the name of Jesus Christ for the forgiveness of sins, and you will receive the gift of the Holy Spirit. For the promise is to you, and to your children, and to all who are far off, even as many as the Lord our God will call to himself.”
in whom you also, having heard the word of the truth, the Good News of your salvation—in whom, having also believed, you were sealed with the Holy Spirit of promise, who is a pledge of our inheritance, to the redemption of God’s own possession, to the praise of his glory.
For you didn’t receive the spirit of bondage again to fear, but you received the Spirit of adoption, by whom we cry, “Abba! Father!” The Spirit himself testifies with our spirit that we are children of God;