From the Hebrew name יִצְחָק (Yitzchaq) meaning "he will laugh, he will rejoice", derived from צָחַק (tzachaq) meaning "to laugh". The Old Testament explains this meaning, by recounting that Abraham laughed when God told him that his aged wife Sarah would become pregnant with Isaac (see Genesis 17:17), and later Sarah laughed when overhearing the same prophecy (see Genesis 18:12).