Avaraham made his way to Eretz Yisrael and wandered around until he reached Shchem (12:6):
וַיַּעֲבֹ֤ר אַבְרָם֙ בָּאָ֔רֶץ עַ֚ד מְק֣וֹם שְׁכֶ֔ם עַ֖ד אֵל֣וֹן מוֹרֶ֑ה וְהַֽכְּנַעֲנִ֖י אָ֥ז בָּאָֽרֶץ
Why did he stop there? Rashi explains עד מקום שכם – להתפלל על בני יעקב כשיבאו בשכם He stopped to daven for the children of Yaakov.
Later in the parsha, Avraham tells Hashem that gifts don't mean anything so long as he does not have any children (15:2-3):
וַיֹּ֣אמֶר אַבְרָ֗ם ה׳ אלקים מַה־תִּתֶּן־לִ֔י וְאָנֹכִ֖י הוֹלֵ֣ךְ עֲרִירִ֑י וּבֶן־מֶ֣שֶׁק בֵּיתִ֔י ה֖וּא דַּמֶּ֥שֶׂק אֱלִיעֶֽזֶר
וַיֹּ֣אמֶר אַבְרָ֔ם הֵ֣ן לִ֔י לֹ֥א נָתַ֖תָּה זָ֑רַע וְהִנֵּ֥ה בֶן־בֵּיתִ֖י יוֹרֵ֥שׁ אֹתִֽי
Sifsei Chachamim asks: If Avraham stopped to daven for the Bnei Yaakov at Shechem, then he must have known that he would have children and grandchildren and great grandchildren! How are we to understand Avraham's complaint?
Netziv says a beautiful pshat in those pesukim later in the parsha which answers the Sifsei Chachamim's question. The words of Avraham's complaint are out of order, as the Ohr haChaim points out: אומרו הן לי - היה לו לומר הן לא נתת לי. Netziv explains that Avraham deliberately put the word לִ֔י first. What Avraham was saying is that even if I have children, what good is it at this point in my life? How can I in my old age, when my best years are long past, raise them and transmit to them my values, my ideology, my torah? In what sense will those children be MY children, given to ME - לִ֔י - if I cannot fully experience raising them?
Netziv's pshat begs the question of why was this was of such concern to Avraham Avinu. In those very pesukim Avraham refers to Elizer as דַּמֶּ֥שֶׂק אֱלִיעֶֽזֶר. Chazal tell us that Eliezer earned this title because he was דולה ומשקה מתורתו לאחרים, Eliezer was capable of teaching to others all the torah of Avraham. Eliezer was such a tzadik that he went alive straight into Gan Eden at the end of his life. Couldn't Avraham have charged Eliezer with the task of teaching his child torah, just like Eliezer taught it to others? Couldn't he have sent the child to cheider, to yeshiva, to learn there?
We see from here, writes R' Chaim Elazari in his Nesivei Chaim, is that no matter how good the yeshiva or cheider or Beis Yaakov, it's no substitute for a parent. You don't become Avraham AVINU through shlichus. Chinuch is a mitzvah she'bigufo, it requires direct interaction between parent and child. When Avraham davened for a child, it is this experience that he pined for.
2) Another great point from R' Chaim Elazari: Avraham did not want to accept any gifts from the King of Sdom lest people say that Sdom, not Hashem, made him rich אִם־מִחוּט֙ וְעַ֣ד שְׂרֽוֹךְ־נַ֔עַל וְאִם־אֶקַּ֖ח מִכׇּל־אֲשֶׁר־לָ֑ךְ וְלֹ֣א תֹאמַ֔ר אֲנִ֖י הֶעֱשַׁ֥רְתִּי אֶת־אַבְרָֽם (14:23). Why did Avraham not have the same compunctions about taking gifts from Pharoah earlier in the parsha?
R' Elazari answers that Hashem's promise that He would make Avraham rich applied only in Eretz Yisrael. Therefore, he did not want Sdom to get any credit. In chu"l, however, Avraham had no guarantee, and could therefore could accept the gifts of others.
In galus, accepting hand outs is acceptable. In chu"l we live in a state of dependency on others for protection and sustenance. Not so in Eretz Yisrael, where we are meant to stand on our own two feet, reliant only on Hashem for our needs. We may not be there yet, but it's important to keep the goal and ideal in mind.