“…Abimelech king of the Philistines looked out a window, and saw, and, behold, Isaac was sporting with Rebecca his wife…(Bereishith 26:8).”
Rabbi Harold Kushner, in a shiur for the New York Board of Rabbis, offered keen insight into what this verse might actually mean. Instead of translating metzahek as “sporting,” Rabbi Kushner suggested going to the root meaning of the word: laughter. Isaac was making Rebecca laugh! (See also Targum Onkelos on this verse.)
The verse relates to a difficult time, when Isaac and Rebecca were in a precarious position vis a vis Abimelech. Isaac feared for his life. Rebecca was posing as Isaac’s sister, and was in a vulnerable state. At this time of crisis, Isaac makes Rebecca laugh. He attempts to soothe her.