How do we know Christ is the touchstone of our faith?

The illustration of Christ as the touchstone comes from the way gold is tested to determine its purity. The question, 'What think ye of Christ?' serves as an acid test of faith. Those with true God-given faith find Christ precious, as stated in 1 Peter 2:7. However, for those without true faith, Christ becomes a stumbling stone (1 Peter 2:8), demonstrating that the gospel itself reveals the purity of one's faith. Essentially, by encountering Christ through the preaching of the gospel, believers' hearts are assayed, leading them to affirm their trust in Him as their only hope of righteousness.