49 The particle אוּלָם (’ulam, “but”) serves to restrict the clause in relation to the preceding clause ( §39.3.5e, n. 107).
50 The force of the imperatives in this sentence are almost conditional—if God were to do this, then surely Job would respond differently. The two imperatives (“stretch out” and “strike”) and the word “hand” all form a bold anthropomorphic sentence. It is as if God would deliver a blow to Job with his fist. But the intended meaning is that God would intervene to destroy Job’s material and physical prosperity.
51 The formula used in the expression is the oath formula: “if not to your face he will curse you” meaning “he will surely curse you to your face.” Satan is so sure that the piety is insincere that he can use an oath formula.
52 See the comments on . Here too the idea of “renounce” may fit well enough; but the idea of actually cursing God may not be out of the picture if everything Job has is removed. Satan thinks he will denounce God.

In other versions

But stretch out your hand and touch all that he has, and he will curse you to your face.”

But now stretch out your hand and strike everything he has, and he will surely curse you to your face.”

But stretch out your hand and strike everything he owns, and he will surely curse you to your face.”

But reach out and take away everything he has, and he will surely curse you to your face!”

But, on the other hand, stretch out your hand and touch all that belongs to him and see whether he will curse you to your face.”

But put forth thine hand now, and touch all that he hath, and he will curse thee to thy face.

Public Domain