People who aren’t Christians have real trouble understanding how Christians can exhibit such an unshakable belief in the existence of God. Christians, in turn, usually point to the incredible vastness, order, and intricacy of creation as the best evidence for God’s existence. This, admittedly, is the Bible’s prescribed way to prove His existence (Romans 1:20).

As for me personally, though, I find that another piece of evidence provides me with even more convincing evidence that God exists. I’m talking about the presence of God the Holy Spirit dwelling within me. You see, I know through daily experience that there is a voice other than my own inside my body. This voice tells me what blog posts to write. It tells me what sermons to preach. It tells me where to send my kids to school. It tells me what cars to buy. It tells me what Christmas presents to buy for my family. It tells me what home-improvement projects to do. In short, this voice guides my life.

Lest you think I’m crazy, let me point out that what I’m describing is nothing less than normal New Testament Christianity. Jesus said that anyone who isn’t born of the Spirit cannot see the kingdom of God (John 3:1-8). Paul said that the Spirit Himself bears witness with the Christian’s own inner spirit to assure that Christian that he or she truly is a child of God (Romans 8:16). Furthermore, Paul also said that if the Spirit of God doesn’t dwell inside a person, that person has no relationship with Jesus (Romans 8:9). John said that Jesus abides within the Christian by way of the Spirit, whom Jesus has given to each Christian (1 John 3:24), and Jude bluntly described lost unbelievers as people who don’t have the Spirit (Jude v.19).

It was the Holy Spirit inside Philip who told him to run and meet the chariot that was carrying the Ethiopian eunuch (Acts 8:29). It was the Holy Spirit inside Peter who told him that three men were coming to see him and that he should go with them and do as they asked (Acts 10:19-20; 11:12). It was the Holy Spirit inside each of the prophets and teachers at Antioch who told those men to separate Saul (Paul) and Barnabas from their group and send them out to do the work the Spirit was calling those two men to do (Acts 13:2). It was the Holy Spirit inside not only Paul but also Silas and Timothy who wouldn’t permit those three men to go to either the Roman province of Asia (Acts 16:6) or the region of Bithynia (Acts 16:7).

Each of these passages shows us that the Holy Spirit is a person, not an “it.” He is a full-fledged member of the holy Trinity that is God. Why is it that so many people think of God the Father and God the Son (Jesus) in terms of personhood but don’t attribute that same status to God the Holy Spirit? If you want to know just how much a person the Holy Spirit is, consider these Bible facts:

• He speaks. (Acts 13:2)
• He is a teacher. (John 14:26; Luke 12:12; 1 Corinthians 2:13)
• He is a guide. (John 16:13)
• He serves as a witness to events. (Acts 5:32)
• He can be resisted. (Acts 7:51)
• He can be grieved. (Ephesians 4:30)
• He (His voice, His influence) can be quenched. (1 Thessalonians 5:19)
• He can be lied to. (Acts 5:3)
• He provides comfort. (Acts 9:31)
• He directs ministries. (Acts 13:4)
• He grants spiritual giftings (abilities for service). (1 Corinthians 12:4-11)
• He considers certain things good. (Acts 15:28)
• He forbids certain plans. (Acts 16:6-7)
• He empowers. (Romans 15:13)
• He inspires (moves to action). (2 Peter 1:21)

Sadly, anyone who has never heard the voice of the indwelling Holy Spirit simply cannot appreciate the reality of the experience. That’s why this valuable piece of evidence for the existence of God doesn’t register with them. Summing up the situation, appreciating the voice of the indwelling Holy Spirit is an “insider’s privilege” that is only available to the members of the club of born-again Christians. But once you’ve heard that voice — especially when the Spirit instructs you to do something that you would never have imagined yourself doing — it’s impossible for you to ever again truthfully deny the existence of God. You just know that He exists. You don’t know it because of mountains, oceans, deserts, stars, planets, solar systems, and universes; you know it because there’s someone living inside you that you genuinely can’t explain away or deny.