Christian faith is not a leap into the dark or a decision to trust God based on no evidence at all. Instead, Christian faith is trust in the Lord for whom there are many evidences. In the first place, there are evidences in the natural world that point us to the God of Scripture. Our Creator has left a testimony to Himself in nature, as Paul tells us in Romans 1:18–32. But we also have the evidence from redemptive history that shows us that the Lord is merciful and has not left humanity without a way of understanding how they can find salvation.
One of the most striking claims of the Christian faith is that there is but one people of God from the garden of Eden onward. There are some differences in how this people has been governed and in the external administrations of the various covenants that have structured God’s relationship to this people over the ages. Nevertheless, there has only been one people and one plan of salvation. God has been faithful to preserve this people from the first act of atonement He made for them in the garden (Gen. 3:21) until the present, and He will be faithful to us forevermore.
Proof of God’s faithfulness to His people is seen in today’s passage when Paul introduces the topic of the righteousness of God manifested in our justification. This righteousness is manifested apart from our doing of His law, but “the Law and the Prophets bear witness to it” (Rom. 3:21–22a). This is a striking statement when we consider the newness of the gospel and the new covenant. The New Testament is clear that in Jesus Christ, God was doing a new thing in the history of His people (Matt. 9:14–18). Yet, the new age that comes with Christ enjoyed a witness under the old covenant in the Law and the Prophets. God was faithful in every age to tell His people of their coming salvation. Whether the promise was of a new Prophet (Deut. 18:15), a new Priest (Isa. 53), or a new King (Ezek. 37:24), God was faithful to speak to His people and tell them of the Savior, and then He was faithful to accomplish what He revealed.
The Lord is faithful to keep His promises and give His people hope for their redemption. We can trust in Him knowing that He never leaves Himself without a witness, that He has not made it too difficult to know Him or His purposes. While we will never know God comprehensively, His testimony to Himself means we can know Him truly and can trust Him to fulfill His promises
God has revealed Himself throughout history and He has kept the promises that He has made in that revelation. Seeing how the Lord has revealed His plan and fulfilled it gives us confidence that He is a trustworthy God. If we want to bolster our trust in the Lord, we must study His promises and how He has kept them throughout the ages.