How do we know God is our only source of good?

In Psalm 16, verse 2, David states, 'I say to the Lord, You are my Lord; I have no good apart from you.' This recognition of God as the only true source of good is essential in understanding our dependence on Him. Throughout the Bible, it is emphasized that everything good comes from above, as seen in James 1:17. Moreover, the idea that apart from Him, we can do nothing is further underscored in John 15:5, indicating that any semblance of good that exists in the world is a reflection of God's goodness.