Who leave the (g) paths of uprightness, to walk in the ways of darkness;
(g) That is, the word of God, which is the only light, to follow their own fantasies which are darkness.

Who leave the paths of uprightness,.... Or "righteousness", or the "right and plain ways" (u); which the light of nature and the law of God, and especially the Gospel of Christ, direct to; and in which they have been trained up, having had a religious education; for it supposes them to have been externally in these ways, since they are said to leave them; for though persons do not easily and ordinarily leave the ways they have been brought up in, yet sometimes they do; and there are instances of it, and such generally are the worst of men;
to walk in the ways of darkness: sin, ignorance, and infidelity; in which they that walk know not where they are, nor whither they are a going, and which must be very uncomfortable as well as dangerous; in which only works of darkness are done, and which lead to blackness of darkness, the darkness of hell; a miserable choice, a sad change this! So Schultens renders it, "ways of horrid darkness".
(u) "semitas rectas", Mercerus; "itinera recta", Piscator; "itinera planissima", Schultens.

paths of uprightness--or, "plainness."
walk--habitually act;

Darkness - Of sin.