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

¶ When a man hath taken a wife, and married her, and it come to pass that she find no favour in his eyes, because he hath found some uncleanness in her: then let him write her a bill of divorcement, and give it in her hand, and send her out of his house.

They say unto him, Why did Moses then command to give a writing of divorcement, and to put her away?

He saith unto them, Moses because of the hardness of your hearts suffered you to put away your wives: but from the beginning it was not so.