Charles Ellicott Commentary Hebrews 5:14

"But solid food is for fullgrown men, [even] those who by reason of use have their senses exercised to discern good and evil." — Hebrews 5:14 (ASV)

Strong meat. Solid food belongs to full-grown men. If they occupied themselves with the rudiments alone, their spiritual senses could not be trained by use (or, habit) in distinguishing between good and evil, truth and falsehood, in the various systems of teaching which men offered as the doctrine of Christ.