God began His work of salvation in the Age of Grace, after the end of the Age of Law. The first incarnation redeemed man from sin through the flesh of Jesus Christ. He saved man from the cross, but man's satanic dispositions lingered on. In the last of days, God judges to purify mankind. It's only when this is done will He end His work of salvation and enter into rest.
The answer from God’s word:
Foolish and ignorant men often regard the normal humanity of Christ as a flaw. No matter how He expresses and reveals the being of His divinity, man is unable to acknowledge that He is Christ. And the more that Christ demonstrates His obedience and humility, the more lightly foolish men regard Christ. There are even those who adopt toward Him an attitude of exclusion and contempt, yet place those “great men” of lofty images upon the table to be worshiped.