I was reading A Time to Laugh; A Time to Listen by Rabbi Yehoshua Kurland. On page 116 he brings down a Chazal (Medrash Tanchumah, Toldos 18) which says, "You make a small opening like one made by the point of a needle and I (Hashem) will expand that opening to the size of the entrance to a grand ballroom."
I opened a Medrash Tanchumah located Parshas Toldos and tried to find 18. However, Parshas Toldos only goes up to 14, not 18.
Does anyone know where this Chazal is located in Parshas Toldos?