9 The form is the simply preterite with the vav (ו) consecutive. However, the speech of Satan is in contrast to what God said, even though in narrative sequence.
10 The preposition בְּעַד (bé’ad) designates interest or advantage arising from the idea of protection for (“for the benefit of”); see §11.2.7a.
11 The meaning of the expression is obscure. It may come from the idea of sacrificing an animal or another person in order to go free, suggesting the expression that one type of skin that was worth less was surrendered to save the more important life. Satan would then be saying that Job was willing for others to die for him to go free, but not himself. “Skin” would be a synecdoche of the part for the whole (like the idiomatic use of skin today for a person in a narrow escape). The second clause indicates that God has not even scratched the surface because Job has been protected. His “skin” might have been scratched, but not his flesh and bone! But if his life had been put in danger, he would have responded differently.
12 The has “make full payment, pay a full price” ( ἐκτίνω).
13 Heb “Indeed, all that a man has he will give for his life.”

In other versions

Then Satan answered the Lord and said, “Skin for skin! All that a man has he will give for his life.

“Skin for skin!” Satan replied. “A man will give all he has for his own life.

“Skin for skin!” Satan answered the Lord. “A man will give up everything he owns in exchange for his life.

Satan replied to the Lord, “Skin for skin! A man will give up everything he has to save his life.

Then Satan answered him and said, “Skin for skin! All that that man has he will give for his life.

And Satan answered the Lord, and said, Skin for skin, yea, all that a man hath will he give for his life.

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