The Hebrew word for Laugh is Tsachaq — pronounced tsaw-khak '. It means: to laugh, mock, play, to jest to sport, play, make sport, toy with, make a toy of .The first mention of laughter in the Bible is in Genesis 17:17. And Abraham fell on his face and laughed. And he said in his heart, Shall one be born to a son of a hundred years? And shall Sarah bear, a daughter of ninety years? What is Abraham laughing at?
Abraham falls on his face. When a person falls on his face, usually two words follow “and worshiped.” He is humble and reverent before the LORD. He laughs in joy with God about himself and Sarah’s fertility. He doesn’t question God’s promise at all in unbelief.
Look at Romans 4:20. Paul tells us that Abraham does not waver at God’s promise in unbelief. This is Scripture interpreting Scripture and is the number one rule in Bible study. Since Abraham never wavered in unbelief, we then know that Abraham’s questions here were in awesome marvel at the power of God not in unbelief of His promise. More at wonder as in the question asked like this: “So this is how powerful you are Lord? You can quicken the dead womb of an old woman?”
Isn’t it wonderful that the first recorded laughter is between God and Man? Now, in Genesis 18:12, Sarah laughs when she hears about God’s promise. Here is the same word, but why does God get upset with Sarah’s laughter and not with Abraham’s?
She lied to God.
She in her heart, she questioned His power. She placed more power in the natural order of things than in the LORD God.
Compare the two passages carefully. Abraham fell upon his face and in his heart he wanted confirmation of God’s promise. Sarah did not believe God. How can we tell she didn’t believe God?
Sarah spoke of her own pleasure (carnal), she spoke about her old husband (natural) and she lied to the LORD.
This is the second time she put the “natural order of things” above God. When was the first time? (Genesis 16) She gave Hagar to Abraham as his concubine. Abraham had only one wife and that wife forced God’s promise in her own way instead of waiting for the Lord’s way and time. This is the classic response mankind has when we don't think God is quick enough in His response. We have such a problem when we focus on what we think is the problem.
Now compare this to Genesis 21:6. How is Sarah’s laughter different? And Sarah said, God has made laughter for me; all who hear will laugh with me.
She is rejoicing. Her laughter is in tune with the LORD and she invites all to hear of the son of her old age. She enjoys the name Isaac which means laughter. I find it wonderful that Isaac’s name never changed during his life as Abram’s and Sarai’s and his own son Jacob’s. I also find it a marvelous, wonderful thing that God promised “Laughter”!
Now, look at Luke 6:21…”those who weep, ye shall laugh.” Sarah’s pining for a son, her tears, turned to joyous laughter. Oh how sweet to laugh with God. He has such a great sense of humor.