Galatians 6:4 addresses comparison directly: "But let every man prove his own work, and then shall he have rejoicing in himself alone, and not in another." The Greek word for "prove" — dokimazeto — means to test by examination, to put to the fire to verify. Paul is describing a shift from comparing your work to someone else's to examining your own work on its own terms. The rejoicing available from this is described as a different kind than comparison can produce — it belongs to yourself, not borrowed from someone else's measurement.
Proverbs 14:30 diagnoses the physical dimension: "envy the rottenness of the bones." The Hebrew word for "rottenness" — raqab — is the word for decay, for the structural disintegration that ruins from the inside out. Instagram comparison is a modern instance of the envy Solomon named as structurally destructive — not just unpleasant but rotting the bones.
Commentary is from a charismatic Protestant perspective, drawing on KJV text and public-domain sources including Spurgeon, Andrew Murray, and Matthew Henry.