Question: "The Fruit of the Holy Spirit – What is faithfulness?"
Answer: Faithfulness is steadfastness, constancy, or allegiance; it is carefulness in keeping what we are entrusted with; it is the conviction that the Scriptures accurately reflect reality. Biblical faithfulness requires belief in what the Bible says about God—His existence, His works, and His character. Faithfulness is a fruit of the Spirit; it is the result of the Spirit working in us. But the Spirit is also our seal of faithfulness. He is our witness to God's promise that if we accept the truth about God, He will save us.
Hebrews 11 gives a long list of faithful men and women in the Old Testament who trusted God. Abel's understanding of God made his sacrifice real and authentic. Noah trusted God's word about the coming judgment as well as God's promise to save his family (Genesis 6-9). Abraham and Sarah believed against all evidence that they would have a child (Genesis 21:1-34). Rahab trusted God to protect her family when the Israelites destroyed Jericho (Joshua 6). Gideon's mustard-seed faith routed an entire army (Judges 6-7).
In that list in Hebrews 11 is the example of Enoch, who "obtained the witness that before his being taken up he was pleasing to God. And without faith it is impossible to please Him, for he who comes to God must believe that He is, and that He is a rewarder of those who seek Him" (vs. 5b-6). Faith, or a faithful commitment to who God says He is, is basic to walking with God. As Jesus traveled, He responded to people's faith and curtailed His involvement where there was no faith (Mark 6:1-6).
Enoch understood that God rewards those who seek Him and trust Him with all their hearts. We trust what God does because we trust Him, not the other way around. In other words, we trust God even when He is silent and we see no miracles. That is part of faithfulness. We know God is reliable, steadfast, and true.
The Old Testament saints also had faith in the invisible work of God (Hebrews 11:3). Abraham never saw his descendants become “as numerous as the stars in the sky.” Moses never entered the Promised Land. And none of the Old Testament saints lived to see their Messiah. But they were faithful. They believed God would do as He promised. They lived by faith and not by sight (2 Corinthians 5:7).
Faithfulness is believing that God is Who He says He is and continuing in that belief despite the vagaries of life. Functionally, that means we trust what God says in the Bible, and not necessarily what the world or our own eyes tell us. We trust He will work out everything for good. We trust He will work His will in us. And we trust that our situation on earth is nothing compared to our future reward in heaven. The only way we can have such faith is by the Holy Spirit's influence. He testifies to the truth and impels us to seek God. The Spirit makes us faithful.