<P> In Genesis 17 when Abram was ninety - nine years old , God declared his new name : `` Abraham '' -- `` a father of many nations '' , and gave him the covenant of circumcision . God gave Sarai the new name `` Sarah '' , and blessed her . Abraham was given assurance that Sarah would have a son . Not long afterwards , Abraham and Sarah were visited by three men . One of the visitors told Abraham that upon his return next year , Sarah would have a son . While at the tent entrance , Sarah overheard what was said , and she laughed to herself about the prospect of having a child at their ages . The visitor inquired of Abraham why Sarah laughed at the idea of bearing a child , for her age was as nothing to God . Sarah soon became pregnant and bore a son to Abraham , at the very time which had been spoken . The patriarch , then a hundred years old , named the child `` Isaac '' ( Hebrew yitschaq , `` laughter '' ) and circumcised him when he was eight days old . For Sarah , the thought of giving birth and nursing a child , at such an old age , also brought her much laughter , as she declared , `` God had made me to laugh , ( so that ) all that hear will laugh with me . '' Abraham held a great feast on the day when Isaac was to be weaned . It was during this banquet that Sarah happened upon the then teenaged Ishmael mocking and was so disturbed that she requested that both he and Hagar be removed from their company . Abraham was initially distressed by this but relented when told by God to do as his wife had asked . </P>
who had a baby at 100 in the bible
Sarah Abraham