who seeks his strength in flesh,
whose heart turns away from the LORD.
-- Jer 17:5-10
Man, tempted by the devil, let his trust in his Creator die in his heart and, abusing his freedom, disobeyed God's command. This is what man's first sin consisted of. All subsequent sin would be disobedience toward God and lack of trust in his goodness.
-- CCC 397
Thursday, Second Week of Lent