Hopefully making theology simpler to understand! (2 Corinthians 1:12)

Keep your heart with all vigilance, for from it flow the springs of life.
Proverbs 4:23, ESV

Job made a covenant with his eyes, and many limit what they eat. But God reminds us everything we look at, listen to, and think about affects the heart (and mind and soul). What we allow in and dwell on affects our thoughts, beliefs, and actions.