Berean Standard Bible (BSB)
Be careful, then, that the light within you is not darkness.
World English Bible (WEB)
Therefore see whether the light that is in you isn’t darkness.
Strong's King James
Take heed{G4648}{(G5720)} therefore{G3767} that the light{G5457} which{G3588} is in{G1722} thee{G4671} be{G2076}{(G5748)} not{G3361} darkness{G4655}.
The F.O.G *
(35) Therefore, look out that the light in you isn't darkness.
The F.O.G Message *
Young's Literal Translation
take heed, then, lest the light that is in thee be darkness;