Acts 2:36-38, Acts 5:30-32, 1 Cor 3:16, 1 Jn 3:24
When we believe in Jesus as the Christ, the Holy Spirit comes upon us. (Acts 2:36-38, Acts 5:30-32)
Acts 2:36 Therefore let all the house of Israel know assuredly, that God hath made the same Jesus, whom ye have crucified, both Lord and Christ. 37 Now when they heard this, they were pricked in their heart, and said unto Peter and to the rest of the apostles, Men and brethren, what shall we do? 38 Then Peter said unto them, Repent, and be baptized every one of you in the name of Jesus Christ for the remission of sins, and ye shall receive the gift of the Holy Ghost.
Acts 5:30 The God of our fathers raised up Jesus, whom ye slew and hanged on a tree. 31 Him hath God exalted with his right hand to be a Prince and a Saviour, for to give repentance to Israel, and forgiveness of sins. 32 And we are his witnesses of these things; and so is also the Holy Ghost, whom God hath given to them that obey him.
When the Holy Spirit comes upon us, we become Christ's, and we become God's temple. (Rom 8:9, 1 Cor 3:16, 1 Jn 3:24)
Rom 8:9 But ye are not in the flesh, but in the Spirit, if so be that the Spirit of God dwell in you. Now if any man have not the Spirit of Christ, he is none of his.
1 Cor 3:16 Know ye not that ye are the temple of God, and that the Spirit of God dwelleth in you?
1 Jn 3:24 And he that keepeth his commandments dwelleth in him, and he in him. And hereby we know that he abideth in us, by the Spirit which he hath given us.