Luke 11:35

33 No one lights a lamp and puts it in a cellar or under a basket. Instead, he sets it on a stand, so those who enter can see the light.

34 Your eye is the lamp of your body. When your eyes are good, your whole body also is full of light. But when they are bad, your body is full of darkness.

Be careful, then, that the light within you is not darkness.

36 So if your whole body is full of light, with no part of it in darkness, you will be radiant, as though a lamp were shining on you.”

37 As Jesus was speaking, a Pharisee invited Him to dine with him; so He went in and reclined at the table.

Do read the surrounding verses too, because the context often says more than a single verse.

Compare

BSB
Be careful, then, that the light within you is not darkness.
KJV
Take heed therefore that the light which is in thee be not darkness.
WEB
Therefore see whether the light that is in you isn’t darkness.
ASV
Look therefore whether the light that is in thee be not darkness.
DARBY
See therefore that the light which is in thee be not darkness.
BLB
Take heed, therefore, [that] the light that [is] in you is not darkness.
ÅB
Se derfor til at lyset i deg ikke er mørke!
OTB
Vær derfor forsiktig at lyset i deg ikke er mørke.
B1930
Se derfor til at lyset i dig ikke er mørke!

Study notes (Tyndale)

Original text and word study

Cross references