How do we know the promise of Proverbs 22:6 is true?

The promise in Proverbs 22:6 stems from God's unwavering commitment and grace toward His people. The assurance that a child trained in the ways of the Lord will not depart from it when he is older is contingent upon God's electing grace. Through the Holy Spirit, God opens hearts, enabling them to respond to the gospel truth. This scriptural principle is further supported by the observation that only those truly taught of God will persevere in faith, confirming that the training alluded to in Scripture is ultimately backed by God's sovereign action in the hearts of His children.