Matthew 19:8
"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."
Cross References (ranked by relevance)
Therefore shall a man leave his father and his mother, and shall cleave unto his wife: and they shall be one flesh.
And Jesus answered and said unto them, For the hardness of your heart he wrote you this precept.
Thus saith the LORD, Stand ye in the ways, and see, and ask for the old paths, where is the good way, and walk therein, and ye shall find rest for your souls. But they said, We will not walk therein.
Yea, they made their hearts as an adamant stone, lest they should hear the law, and the words which the LORD of hosts hath sent in his spirit by the former prophets: therefore came a great wrath from the LORD of hosts.