why Ya'akov did not daven for Rachel to have children

Rachel reacted to her inability to have children while by beseeching Ya’akov Avinu to daven for her. Rather than respond with compassion, Ya’akov turns her away and refuses. How, asks the Ramban, are we to understand Ya’akov’s refusal to daven for his own wife when in Tanach we find tzadikim who opened their hearts to daven for women who were complete strangers? The Taz answers that tefillah has the power to overcome spiritual obstacles like a gezeirah preventing a person from having children. Rachel, however, was physically unable to have children – Chazal tell us she was born without a uterus. Correcting this situation required not just overturning a gezeirah, but a “beriyah yesh m’ain”, a completely new act of creation, and according to the Taz, that lies outside the scope of what tefillah can accomplish. This is what Ya’akov meant in responding “Hatachas Elokim anochi”, “Am I in place of G-d” – the necessary remedy in this case was outside the scope of a tzadik’s power, but rested only in G-d’s hands. What this tells us about the nature of tefillah is discussed by my wife on her blog, so I will just add one additional point. In light of this Taz we can better understand Moshe Rabeinu’s response to Korach’s rebellion – “Im briya yivra Hashem…”, if Hashem will create a new opening in the earth to punish Korach, it proves definitively the error of the rebellion. Had Korach been punished through some change of the natural order, one might conclude that the punishment was a result of Moshe’s power as a tzadik to redirect nature. However, if the punishment comes through a new creation, this could only be a response directly from Hashem, as it is not something within the scope of a tzadik’s power to bring about.