Quote by D.A. Carson

“Apart from the light brought by the Messiah, the incarnate Word, people love darkness because their deeds are evil (3:19), and when the light does put in an appearance, they hate it, because they do not want their deeds to be exposed (3:20). In fact, wherever it is true that the light shines in the darkness, it is also true that the darkness has not understood it (taking katelaben as in the NIV). Reading v. 5 this way anticipates the rejection theme that becomes explicit in vv. 10–11. Alternatively, even if katelaben means something like ‘did not overcome it’ (see Additional Note), it is quite possible that John, subtle writer that he is, wants his readers to see in the Word both the light of creation and the light of the redemption the Word brings in his incarnation.”