Job 1:12

And the Lord said unto Satan, accepting the challenge contained in his words, Behold, all that he hath is in thy power; only upon himself put not forth thine hand. Satan thereby received permission to deprive Job of all his property, of all his immense wealth; but he was not allowed to touch the person of Job. The obvious intention of the Lord, in granting this permission to Satan, was to test the integrity and the piety of Job, to prove his sincerity over against the devil's sneering insinuations. It was a phase of the battle of light with darkness. So Satan went forth from the presence of the Lord, ready to begin his work of destruction, for he is a murderer from the beginning; plunder and destruction are his delight. The thought that the Lord, in permitting misfortune to come upon His children in this world through the hatred of Satan, has the purpose of proving the sincerity of the believers should stimulate the latter to meet the attacks of the devil with the spirit of true loyalty to their Father in heaven.