If we say that we have fellowship with him, and walk in darkness, we lie, and do not the truth:
Ver. 6. If we say that, &c.] As they do that profess to know God, but in works do deny him, Titus 1:16. See Trapp on " Tit 1:16 "
And walk in darkness] There is a child of light that walks in darkness, Isaiah 50:10, but that is in another sense. The wicked also that are here said to walk in darkness have their sparkles of light that they have kindled, Isaiah 50:10, but it is as a light smitten out of a flint, which neither warms nor guides them, but dazzleth their eyes, and goes out, so that they lie down in sorrow.