Whether the light
Is not darkness!”
σκόπει οὖν μὴ τὸ φῶς τὸ ἐν σοὶ σκότος ἐστίν.
Luke uniquely indicated that Jesus asked them to consider or take heed (σκόπει οὖν) whether or not the light (μὴ τὸ φῶς) in them (τὸ ἐν σοὶ) was or becoming darkness (σκότος ἐστίν). In other words, how bright was their light? Was it getting dim? Was the evil dark over taking them? Jesus warned them about bad darkness gaining on the good light in them. Do you have bright eyes?