The Holy Spirit Click here for my YouTube videos on salvation.
The Holy Spirit is called the Spirit of God or the Spirit of Jesus and He is sent into a person's life when they accept Jesus as their Lord and Saviour. The Spirit's work is to lead believers in all truth (John 16:13). He also convicts us of sin, righteousness and the coming judgment (John 16:8) and glorifies Jesus (John 16:14).
The Bible says in Romans 8:7, "the sinful mind is hostile to God. It does not submit to God's law, nor can it do so." From this verse we can see that our sinful nature rebels against God and we are unable to follow His laws. When a person turns their back on their sinful way of life (repents), and turns to Jesus for forgiveness, God sends the Holy Spirit into the person to give them power over their sinful nature. Through the Holy Spirit a person is able to begin a new life, leaving their old, sinful life behind ... this is known as being born again. Although we cannot live a sinlessly perfect life, we must keep from deliberate, ongoing sin and this can only be done through the power of the Holy Spirit. This is discussed in more detail in the article How Do We Know If We Are Saved?