The Gift of the Holy Spirit
—Who receives it, and what is its nature?
Peter promised "the gift of the Holy Spirit" to all believers who would repent and be baptized. He made it quite clear as to how many receive the forgiveness of sins and the gift of the Spirit. "The promise is to... as many as the Lord our God shall call" (Acts 2:38-39).
1 Universal Gift
Jesus promised that God will give the Holy Spirit to anyone who asks him in the proper way (Luke 11:9-13). Note "everyone" in verse 10. Anyone who comes to Christ will receive the Spirit (John 7:37-39). Note "any one" in verse 37.
All those who are saved through "the washing of new birth" have the Holy Spirit "poured out abundantly" upon them so that they, having been justified by faith, may become heirs. This is true of all God's heirs (Titus 3:4-7).
Speaking to all Christians, Paul said, "Now if anyone does not have the Spirit of Christ, he is not his". Paul said that you have life from Christ only "if indeed the Spirit of God dwells in you" (Romans 8:5-17, esp v.9,11).
The idea that some Christians lack the Spirit is therefore incorrect. If you lack the Spirit, you do not belong to Christ. If you are a Christian, if you belong to Christ, then you already have the Holy Spirit; he indeed dwells in you. There is no need for you to "get" the Spirit.
2 The Seal of the Spirit
Those who have saving faith in Christ are "sealed in Him with the Holy Spirit". The Spirit is given to them "as a guarantee" of their inheritance. (Ephesians 1:11-14). The Holy Spirit is given to those who have hope having been justified by faith. Their "hope does not disappoint", because the Spirit has been given them (Romans 5:5).
Those who are "in the flesh" are enemies of God, but those who are "in the Spirit" are heirs of God (Romans 8:1-17). The latter are so because not only are they in the Spirit, but the Spirit dwells in them (as stated in verse 9).
The repeated use of "if" [ ει ] in verses 9-17 is rhetorical. It expresses causality in the sense of "since". It does not express doubt. The condition is affirmed in verse 15, so there is no question of doubt.
Similar examples of this sense of the word "if" may be found elsewhere in the New Testament (eg Philippians 2:2, 2Corinthians 2:10, 1Peter 2:3).
The Spirit is given to guarantee eternal life. This includes the guarantee that we will always be able to fulfil the conditions required for inheriting eternal life. We are guaranteed that as a right, and nobody can take that right away from us.
3 The Work of the Spirit
The Holy Spirit is active in our lives. Like so many things in our faith and religion, we can fully accept the gift of the Holy Spirit and his work among us and in us, without fully understanding how he "operates".
We know, however, something of what he does: we are strengthened by the Spirit (Ephesians 3:16), and helped to be abundant in the fruit of the Spirit (Galatians 5:22-25). The Holy Spirit intercedes for us when we pray (Romans 8:26).
We may need to permit the Holy Spirit to work more abundantly in our lives. Perhaps we are hindering him. For he can work in us only to the extent that we prayerfully follow his word. The possessions and cares of this world can, if we let them, push God out of our lives.
Note:— The gift, renewing, outpouring, indwelling, and seal of the Spirit, are best understood as all being one and the same thing. It makes for complication and confusion when we try to make distinctions between them. These are likely to be "distinctions without difference".