For he is cast into a net by his own feet, and he walks on its mesh.
The rest of Bildad's discourse is entirely taken up in an elegant description of the miserable condition of a wicked man, in which there is a great deal of certain truth, and which will be of excellent use if duly considered - that a sinful condition is a sad condition, and that iniquity will be men's ruin if they do not repent of it.
Commenting on Job 18:5-10
The gin shall take him by the heel,.... And hold him fast, so that he shall not be able to get away, especially out of such as are set by God himself; for God has his nets, and snares, and gins for wicked men, and such plenty of them, that he even is said to rain them on them; yea, he himself is a gin...
he walketh upon--rather, "he lets himself go into the net" [UMBREIT]. If the English Version be retained, then understand "snare" to be the pitfall, covered over with branches and earth, which when walked upon give way (Psa 9:15; Job 35:8).