Truth has no meaning apart from God.
Truth cannot be adequately explained, recognized, understood, or defined without God as the source. Since He alone is eternal and self-existent and He alone is the creator of all else, He is the fountain of all truth.
If you don’t believe that, try defining truth without reference to God, and see how quickly all such definitions fail. The moment you begin to ponder the essence of truth, you are brought face-to-face with the requirement of a universal absolute—the eternal reality of God. Conversely, the whole concept of truth instantly becomes nonsense as soon as you attempt to remove the thought of God from your mind.
That, of course, is precisely how the apostle Paul traced the relentless decline of human ideas in Romans 1:21–22: “Even though they knew God, they did not honor Him as God or give thanks, but they became futile in their speculations, and their foolish heart was darkened. Professing to be wise, they became fools.”
Read more: https://www.gty.org/library/blog/B170913/no-god-no-truth-know-god-know-truth