'Affinity' in the Bible

And Solomon made affinity with Pharaoh king of Egypt, and took Pharaoh's daughter, and brought her into the city of David, until he had made an end of building his own house, and the house of the LORD, and the wall of Jerusalem round about.

Now Jehoshaphat had riches and honour in abundance, and joined affinity with Ahab.

Should we again break thy commandments, and join in affinity with the people of these abominations? wouldest not thou be angry with us till thou hadst consumed us, so that there should be no remnant nor escaping?

And after the course of years they shall join affinity; and the king's daughter of the south shall come to the king of the north to make equitable conditions: but she shall not retain the strength of her arm; neither shall he stand, nor his arm; and she shall be given up, she and they that brought her, and he that begat her, and he that strengthened her in those times.