Sermon OverviewScripture Passage: Romans 8:9The distinguishing mark of a Christian is the Holy Spirit in him. We can know a person has been saved if the Holy Spirit dwells in him. Romans 8:9 says, “But you are not in the flesh but in the Spirit, if indeed the Spirit of God dwells in you. Now if anyone does not have the Spirit of Christ, he is not His.”This passage describes the Holy Spirit as the Spirit of life, of Christ, and of adoption. And if we want to get to know our best friend, the Holy Spirit, we must understand the ways He ministers to us.As the Spirit of life, He gives us life. The people who are truly saved live by the impartation of life, while the unsaved live a mere imitation of life. Our spirit is the part of our nature that enables us to know God. We are spiritual corpses until God breathes His Spirit into us. From that moment on, God’s Spirit bears witness to ours that we are children of God.Second, the Holy Spirit in us glorifies the Lord. His Spirit is called the Spirit of Christ. It is Jesus in us who is the Holy Spirit; His presence in us glorifies God.Adrian Rogers says, “If you want to know whether a person has the Holy Spirit, don’t ask him to speak with tongues, ask if he is like Jesus.”Third, He is called the Spirit of adoption. When we get saved, we are spiritually adopted into the family of God. Romans 8:15 says, “For you did not receive the spirit of bondage again to fear, but you received the Spirit of adoption by whom we cry out, “Abba, Father.”The Holy Spirit guarantees our legacy as children of God. He is there to attest to and make real what legally transpired when we became sons and daughters of God. By law, a man could disinherit a natural son, but he could not legally disinherit an adopted son.By adopting us into His family, God has locked himself into this new relationship with us. We not only have a new relationship, but we also have a new assurance and a new certainty of our riches as co-heirs with Christ.Apply it to your lifeDo you have the distinguishing mark of a Christian, which is the Holy Spirit? Remember this Good News: the Spirit gives us life, glorifies the Lord, and guarantees our inheritance.