Bible Verses About Marriage: Were allowed divorce from, because of hardness of their hearts

If a man take a wife, and have her, and she find not favour in his eyes, for some uncleanness: he shall write a bill of divorce, and shall give it in her hand, and send her out of his house.

They say to him: Why then did Moses command to give a bill of divorce, and to put away?

He saith to them: Because Moses by reason of the hardness of your heart permitted you to put away your wives: but from the beginning it was not so.