That which he laboured for shall he restore, and shall not swallow it down: according to his substance shall the restitution be, and he shall not rejoice therein.
Image from food which is taken away from one before he can swallow it.
Restitution - (so Proverbs 6:31.). The parallelism favours the English version "according to his substance, so shall be his restitution'-literally, 'according to the substance of his recompence' or restitution), rather than the translation of Gesenius, 'As a possession to be restored in which he rejoices not.'
He shall not rejoice - his enjoyment of his ill-gotten gains shall then be at an end (Job 20:5).