Doctrine (what we choose to believe) is a matter of the heart. Choosing to listen to the doctrines of men is a heart decision and reveals who is choosing to be "of God" and who is choosing to be "not of God." (Mark 7:6-9; John 8:47; 2 Timothy 4:2-4) The enemy of all souls will drown his victims in a million pounds of truth in order to kill them with one heretical ounce (Galatians 5:9). Error crouched in much truth is the way many are destroyed. Is all of your doctrine sound?