no contingencies

The first Rashi on the parsha tells us that Hashem told Avraham lech lecha, to go to Eretz Yisrael, because only there would he be zoche to have children.  

Avraham and Sarah were barren for many years, and yet, as we will see in next week's parsha, Hashem did a miracle and they were able to have Yitzchak in their old age.  So what does Rashi mean that Avraham had to travel to Eretz Yisrael to be zoche to children?  If Hashem could make it possible for Sarah to give birth at 90 and Avraham at 100, he could also make it possible for them to have children in chutz la'aretz?

Sefas Emes (5639) explains that Avraham not being able to have children in chu"l is not a "din" in Avraham Avinu, but rather is a "din" in chutz la'aretz.  Hashem could have made a miracle and Avraham could biologically have had a child in Charan, but raising a Yitzchak Avinu, someone who would continue to build the nation of Klal Yisrael, can only be done on the holy soil of Eretz Yisrael. 

There were as many ovdei avodah zarah in chu"l as in Eretz Yisrael in Avraham's time.  The need for Yitzchak to be born in Eretz Yisrael has nothing to do with the environment being more conducive to Torah -- there were not more yeshivos, more shuls, etc. in Eretz Yisrael.  Avraham was the center of Torah, wherever he was.  It's very clear, despite the confusion that sadly many people have, that being in Eretz Yisrael is a value in its own right, not just a hechsher to allow us to do more mitzvos or create a bigger, better makom Torah (see first section in Orot).

Ramban asks why it is that the Torah does not give us any background information on Avraham Avinu before telling us that G-d commanded him to go to Eretz Yisrael.  In last week's parsha we are told right off the bat, "Noach ish tzadik tamim haya b'dorosav," and so we know why he merited being saved and how the rest of the story follows.  We know nothing about who Avraham his and why G-d told him to pick himself up and travel to Eretz Yisrael -- it's like the narrative begins medias res.  

Maharal (in Derech haChaim) answers that this is a deliberate omission.  G-d's choice of Avraham Avinu = Klal Yisrael and Eretz Yisrael as our homeland is not contingent on mitzvos, on zechuyos, even on kabbalas haTorah.  We say in birchas haTorah, "asher bachar banu m'kol ha'amim v'nasan lanu es Toraso."  We were Hashem's chosen nation -- before we ever received the Torah.  The former made the latter possible, not the other way around (R' Tzvi Yehudah).

Later in the parsha Hashem comes to Avraham and tells him that Sarai's name will be changed to Sarah and she will have a son.  Avraham responds (17:18), "Lu Yishmaeil yichyeh lifanecha!"  Rashi explains: "I am not worthy of this schar."  Avraham's response in baffling.  When Yishmael was born, Sarah complained (16:5), "chamasi alaecha," that Avraham shortchanged her and should have davened on her behalf so that his son would be born through her and not Hagar.  We see that Sarah longed for children.  Even if Avraham was satisfied with having Yishmael, he should have been overjoyed on Sarah's behalf.   He should have welcomed the news that Sarah's wish for a child would be fulfilled.  How could Avraham dismiss Hashem's promose and say that Yishmael is enough?

Shem m'Shmuel answers that the key to understanding Avraham's response is Rashi's comment about matan schar, the child being a reward.  Avraham was saying to Hashem that if we are talking schar and onesh, what is deserved and earned or not earned, then the game stops at Yishmael.  If the continuity of Avraham's legacy is contingent on zechuyos, then it's not a legacy that will lead to a Yitzchak Avinu and is not a legacy that can create a Klal Yisrael.  We don't play the contingency game.  The promise of Klal Yisrael is not dependent upon matan schar, upon earning something through zechuyus.  The promise of a Yitzchak has to be no questions asked, no conditions set, no requirements or contingencies.  (You can look up the Sm"S for his explanation of why Hashem framed the promise in the way he did, but that's a different story.)  That's the promise of Klal Yisrael.