Passage
The light of the body is the eye: if therefore thine eye be single, thy whole body shall be full of light.
The light of the body is the eye: if therefore thine eye be single, thy whole body shall be full of light.
Matthew 6:20 But lay up for yourselves treasures in heaven, where neither moth nor rust doth corrupt, and where thieves do not break through nor steal:
Matthew 6:21 For where your treasure is, there will your heart be also.
Matthew 6:22 The light of the body is the eye: if therefore thine eye be single, thy whole body shall be full of light.
Matthew 6:23 But if thine eye be evil, thy whole body shall be full of darkness. If therefore the light that is in thee be darkness, how great is that darkness!
Matthew 6:24 No man can serve two masters: for either he will hate the one, and love the other; or else he will hold to the one, and despise the other. Ye cannot serve God and mammon.
The verse centers on "light", "body", "therefore", "thine", "single", "whole", and "shall". It is saying that the verse draws attention to "light" and "body", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 21's "For where your treasure is there will..." into verse 23's "But if thine eye be evil thy...", so "light" and "body" belong inside that flow. In Matthew context, the local focus is Christ, faith, and discipleship.
A plain takeaway is to answer the verse's own emphasis on "light" and "body" with trust shaped by these words, not by a vague optimism outside the passage.