31 Let him not deceive himself by trusting what is worthless, for he will get nothing in return.

Read Job 15:31 Using Other Translations

Let not him that is deceived trust in vanity: for vanity shall be his recompence.
Let him not trust in emptiness, deceiving himself, for emptiness will be his payment.
Let them no longer fool themselves by trusting in empty riches, for emptiness will be their only reward.