How do we know that lust is a form of adultery?

In Matthew 5:28, Jesus states, 'But I say unto you, that whosoever looketh on a woman to lust after her hath committed adultery with her already in his heart.' This profound teaching illustrates that adultery is not solely about physical actions but also involves internal desires and fantasies. The seriousness of this reveals that God's standards extend beyond mere behavioral compliance to the intentions and thoughts of the heart. Thus, every individual, in their natural state, is guilty because, as the Scriptures affirm, all have sinned and fall short of the glory of God (Romans 3:23). This underscores the importance of recognizing our total depravity and the need for a transformative work of grace to change our hearts.