When we truly repent and believe in his Son, God sends us his Holy Spirit to live in us. Through his Holy Spirit, God revives our dead spirit to have fellowship with him and to worship him in spirit and in truth. Before, our spirit was dead, but after we repent and believe, our spirit is made alive.
The Bible calls this experience being born again. Jesus said:
[John 3:3-8] Unless one is born again he cannot see the kingdom of God. Unless one is born of water and the Spirit, he cannot enter the kingdom of God. That which is born of the flesh is flesh, and that which is born of the Spirit is spirit. Do not marvel that I said to you, ‘You must be born again.’ The wind blows where it wishes, and you hear its sound, but you do not know where it comes from or where it goes. So it is with everyone who is born of the Spirit.
The Bible also says:
[1 Peter 1:3] According to his great mercy, God has caused us to be born again to a living hope through the resurrection of Jesus Christ from the dead.
Have you experienced this spiritual birth? This is not something optional. Jesus himself said that unless we are born again of the Spirit, we cannot enter the kingdom of God.
This experience was not available before Jesus’ resurrection and his ascension to heaven, but God announced it through the great prophet Jeremiah some six hundred years before Jesus:
[Jeremiah 31:31-34] Behold, the days are coming, declares the Lord, when I will make a new covenant with the house of Israel and the house of Judah, not like the covenant that I made with their fathers on the day when I took them by the hand to bring them out of the land of Egypt, my covenant that they broke, though I was their husband, declares the Lord. This is the covenant that I will make with the house of Israel after those days, declares the Lord: I will put my law within them, and I will write it on their hearts. And I will be their God, and they shall be my people. And no longer shall each one teach his neighbor and each his brother, saying, ‘Know the Lord,’ for they shall all know me, from the least of them to the greatest, declares the Lord. For I will forgive their iniquity, and I will remember their sin no more.
Because the Holy Spirit of God now lives in us, we will naturally love God and our fellow humans, obeying the greatest two commandments. We will have God’s thoughts and desires in our heart and mind. We will obey God out of love and will always try to please him. We will no longer continue to live in sin. We will no longer be slaves of sin. We will be free to follow our conscience, the will of God as revealed in the Bible, and the leading of the Holy Spirit in us. The Bible calls this walking after the Spirit. If we do that our life will change into what God desires.
[Galatians 5:22-24] The fruit of the Spirit is love, joy, peace, patience, kindness, goodness, faithfulness, gentleness, self-control; against such things there is no law. And those who belong to Christ Jesus have crucified the flesh with its passions and desires.
Have you crucified your sinful nature with its passions and desires? Or are you just religious? Jesus said in his famous sermon on the mount:
[Matthew 5:8] Blessed are the pure in heart, for they shall see God.
Are you pure in heart? That’s what God wants, not dead religious practices. Without a pure heart, your religion is useless.