Correction - his people have become corrupt.  Even in the days of Moses the Israelites were sacrificing their children to Molech.  During the times of the judges polytheism and idol worship were so prevalent that the people placed Asherah poles in the tent of meeting.  The God of the Israelites was well aware of their apostasy and likened them to whores that would spread their legs for any passer-by.  Yes, he was well aware of the problem and even said that his name was blasphemed by the nations because of them.  Jesus also rebuked the religious leaders for their hypocrisy and their apostasy, likening then to a den of vipers and stating that they travelled far and wide to proselytize, only to make their proselytes twice as much a child of hell as they themselves were.  Indeed, they have all become corrupt.  Jesus came to save that which was lost, but his people rejected and crucified him.  Therefore the kingdom of God was taken from them and given to the gentiles.  In fact this was mystery from the beginning but revealed to the apostles: that God hardened the hearts of the Israelites that salvation might be offered unto the gentiles as well.