Matthew Poole and continuators on Job 18:7

7. The steps of his strength shall be straitned , and his own Counsel shall cast him down .

i. e. His strong steps, by a vulgar Hebraism. By steps he means his Counsels, as the next branch explains it, his attempts and actions, and by steps of strength, such of them as seem to be most firm and settled, contrived with greatest strength of Understanding, and carried on with great resolution and might.

i. e. Shall be hindred and entangled. He shall be cast into great difficulties, and troubles, and perplexities, so that he shall not be able to proceed, and to accomplish his Enterprizes, but shall find himself ensnared by his own devices, as the next words declare it. This Phrase is used also, Prov. 4. 11, 12. and it is opposed to the enlarging of a mans way or steps, which signifies success and prosperity, as Psal. 4. 1. & 31. 8.

He shall be undone by his own contrivances, either because God will give him up to dangerous and destructive mistakes of his way, or because God will oppose him, and turn his own devices against him; which he can easily do, by throwing in unexpected accidents.