The Holy Spirit is the third person of the Trinity, truly God and therefore co-equal with the Father and the Son (MAT. 28:19; JHN. 14:26; Acts 5:3-4; 2 COR. 13:14). Since He is spirit, He does not have to be seen or felt in order to be close to us. Since He is holy, He must be met on "holy ground." This is why people who have not separated themselves from sin lack the awareness of His presence.

He acted with the Father and Son in creation (GEN. 1:2), equipped people to do God's service (EX. 31:1-5; NUM. 11:16-17), renewed nature (PS. 104:30), came upon Israel's kings (1 SAM. 16:13), inspired Israel's prophets and the men who wrote the Scriptures (1 PET. 1:10-12; 2 PET. 1:21), and worked in the hearts of people to lead them to believe God and do His will (Acts 7:51).

This shows how willing God is to provide supernatural strength to those who want to serve Him. Those who want to do God's will don't have to do it in their own power.

He draws attention to Christ (JHN. 16:13-14), empowers God's messengers (1 THES. 1:5), brings conviction to sinners (JHN. 16:8-11), and produces the new birth (JHN. 3:5; TIM. 3:5). 

For these reasons, no person is too bad or too hardened to be converted to Christ. No person is so evil that he cannot be reached or cannot be saved. The purpose of God has never been to save only good people or to bring deliverance only to those who were naturally endowed with qualities that would make them desirable prospects for the kingdom of heaven. God sent His Spirit into the world to come to the rescue of all kinds of people - even the very worst and most hateful.

He permanently indwells the true believers and marks us out as God's possession (MAT. 7:21; JHN. 14:21-23 ROM. 8:9; 1 COR. 6:19). He seals us to guarantee our ultimate salvation (2 COR.1: 21-22; EPH. 1:13-14; 4:30). He fills us when we yield to Him, giving us power for life and ministry (Acts 6:3; 13:9-12; EPH. 5:18-21). He produces Christian character in us (GAL. 5:22-23). He teaches us (1 COR. 2:10). He intercedes for us when we cannot pray (Rom. 8:26-27). He enables us to discern false teaching about Christ (1 JHN. 2:20-27). He assures us that we are God's children (ROM. 8:16). He equips us to serve one another (ROM. 12:3-8; 1 COR. 12:1-31). He guides us (ROM. 8:14).

We are inclined to assume that what we see in the mirror is what counts. But what really counts is what the Holy Spirit can do in a heart that is given unreservedly to Him.

We are warned about sinning against the Holy Spirit by grieving Him through disobedience (EPH. 4:30), lying to Him (Acts 5:3), quenching Him with a negative attitude (1 THES. 5:19), resisting Him (Acts 7:51), and insulting Him (MAT. 12:31-32, LK. 12:47; HEB. 6:4-6; 10:26-29; 2^nd PET. 2:20-21).

For this reason, we should be far more concerned about maintaining a good relationship with the Spirit than we are about staying on good terms with our spouse, children, parents, some churches, employer, or friends.