And the Lord restored Job’s losses when he prayed for his friends. Indeed the Lord gave Job twice as much as he had before. Job 42:10

This verse makes several things clear.
First, the Lord restored Job’s losses.
Job may work hard and long hours. He may barter with neighbors to get stock and supplies. Perhaps he rebuilt but it was God that restored him.
This only happened after he prayed for his friends.
I do not believe God held this over Job’s head as some kind of ransom – pray for your friends and I’ll restore everything – it’s just Job’s nature to pray and sacrifice for others.
Jesus said the greatest in heaven is the servant of all.
Indeed, when you give and help others in their time of need, they often return your generosity by giving and helping you in your time of need.
Job’s restoration equals twice as much as his loss.
He even started a new family, which may include a new wife since his first one wanted him dead.
In a time dominated by men, it is unusual to see the names of Job’s three daughters and not the names of the sons. The daughters also receive an inheritance, something else usually given to males.
His daughters are praised as the most beautiful in the land.

Job began with 7,000 sheep, 3,000 camels, 500 yoke of oxen, 500 female donkeys, and 10 children (7 sons and 3 daughters).
Job ended with 14,000 sheep, 6,000 camels, 1,000 yoke of oxen, and 1,000 female donkeys.
As the Bible states, this is double.
You may notice he still ends up with 10 children – 7 sons and 3 daughters, which is not twice as much. However, Job saw his children and grandchildren for four generations. (Job 42:16) I think that’s more than doubled.

God completely restores!