First, I'll agree with Ryo and say that the HS does not indwell all people. To get a little more specific:
No one, prior to the ascension of Christ, was indwelt with the HS. In the OT, we find absolutely no record of anyone being indwelt. However, it is obvious that the OT is familiar with the Holy Spirit, as 1) David asked God not to take away His "Holy Spirit" (Ps. 51:11), 2) Samuel made it clear that the Spirit of God had departed from Saul (1 Sam. 16:14), 3) it was the "Spirit of God" that hovered over the deep (Gen. 1:2), etc. Actually, I encourage you to run a search through the OT on the words "spirit" and "came upon" (or "fell upon", depending on your translation).
What we see is that the Spirit of God was with some people and not with others. When He was with them, they moved in His power. Specifically, the Spirit of God enabled men to perform certain tasks, (i.e. run a kingdom or prophecy.) But in all this, we no where find any reference of the Holy Spirit being inside of a person.
When we come to the NT, we see that Jesus says that John the Baptist was the greatest prophet up until then. But notice what He says following:
- What did you go out into the desert to see? A reed swayed by the wind? If not, what did you go out to see? A man dressed in fine clothes? No, those who wear fine clothes are in kings' palaces. Then what did you go out to see? A prophet? Yes, I tell you, and more than a prophet. This is the one about whom it is written: 'I will send my messenger ahead of you, who will prepare your way before you.' I tell you the truth: Among those born of women there has not risen anyone greater than John the Baptist; yet he who is least in the kingdom of heaven is greater than he. (Matthew 7b-11, NIV)
Without getting too deep, the kingdom of heaven had not yet come, and thus, it cannot be equated with Israel. It came with Christ, and as such, John could not be said to be in it (prior to his own salvation by belief in Christ). Why, then, is the least in Christ's kingdom greater than greatest of the Old Testament prophets?
The answer is simply that the Spirit indwells those who are in the Kingdom. In fact, we see that it is the indwelling of the Spirit that sanctifies us positionaly. Thus, only Christians are indwelt by the Spirit. For more, see 2 Cor. 1:22; 5:5; Eph. 1:4.
On a final note, the definitive answer comes from Jesus Himself. He says in John 14:15-17
- If you love me, you will obey what I command. And I will ask the Father, and he will give you another Counselor to be with you forever— the Spirit of truth. The world cannot accept him, because it neither sees him nor knows him. But you know him, for he lives with you and will be in you. (ESV)
Take special note that the Spirit would be with and in them. That is future tense. He was not, at that time, with and in them. Again, the Spirit was with only those whom God had chosen Him to be with and was IN no one until that time. But, at some point in the future (after Christ's ascension), the Spirit would be not only WITH, but IN them.
Once again, then, we see that the HS resides in, and only in, the Christian.
God bless
but no worries 
) Acts 19:1-7 