What does Matthew 6:22 mean?

Matthew 6:22 KJV
The light of the body is the eye: if therefore thine eye be single, thy whole body shall be full of light.

Matthew 6:22 MKJV
The light of the body is the eye. Therefore if your eye is sound, your whole body shall be full of light.

Matthew 6:22 NKJV
“The lamp of the body is the eye. If therefore your eye is good, your whole body will be full of light.

Matthew 6:22 KJV 2000
The light of the body is the eye: if therefore your eye be sound, your whole body shall be full of light.

Interlinear KJV

The light /luchnos/ of the body /soma/ is /esti/ the eye: /ophthalmos/ if /ean/ therefore /oun/ thine /sou/ eye /ophthalmos/ be /o/ single, /haplous/ thy /sou/ whole /holos/ body /soma/ shall be /esomai/ full of light. /photeinos/

Albert Barnes’ Commentary

The light of the body is the eye, or, the eye is the lamp of the body. As the eye is to the physical body the chief organ and medium of forming conceptions of independent objects, so is the spiritual eye of the inner man of the soul the light of the soul by which proper conceptions of spiritual truths are formed and admitted unto reformation and growth in truth and grace.

— If therefore thine eye be single, — not double (see Mt 6:24), in which condition no object can be distinctly seen with the physical eye. Likewise if the spiritual eye of the soul is beclouded with carnal lust and fleshly fancies, it is unable to perceive the spiritual lessons of the pure Gospel.

— Thy whole body shall be full of light, — the inner man shall be all light filling the entire body with the spiritual light of the Gospel.

British Family Bible

The light of the body is the eye: Rather, the eye is the lamp of the body. This whole passage is metaphorical; by the body is here meant the mind, and by the eye the turn and disposition of the mind in matters of religion. As when the eye, which is the light of the body, is so vitiated as to give no light, the whole body is full of darkness; so, when the reason or understanding, which is the inward light, is vitiated, the whole soul is darkened; and, the darkness being total, it is therefore very great. Bp. Pearce.

— thine eye be single, Entire, sound, free from disorder. If the understanding and will be distempered, we can no more perceive and relish our true happiness than we can see clearly when our sight is defective. Bp. Mann.