After Pharoh sends Avraham and Sarah away from Mitzrayim, Avraham returns home on the same path that he had traveled on his way to Mitzrayim. The posuk says, "He proceeded on his journeys, from the south till Beis-El, until the place where his tent had stood at first, between Beis-El and Ai, to the place of the altar which he had erected there at first, and there Avraham called out in the name of Hashem" (Lech Lecha, 13:3-4). Rashi comments that the phrase "He proceeded on his journeys" implies that Avraham traveled on the same route and stayed in the same lodgings in which he had stayed overnight on his way down to Mitzrayim. This teaches proper conduct that a person should not choose different lodgings when traveling on the same route.
Why is this behavior so significant? The Ksav Sofer explains that what made Avraham's behavior noteworthy is the fact that he was now much wealthier than before. After Pharoh was forced to return Sarah, he showered Avraham with gifts. And as a result, "Avraham was very heavy with livestock, with silver and gold" (13:2). Generally, when a person becomes wealthy, he changes his lodgings. He upgrades his home; he vacations in greater style. He raises his standard of living.
The posuk is teaching that Avraham Avinu was different. He was not drawn to luxuries. Rather, he was focused on avodas Hashem, on spreading Hashem's name to all those who came in contact with him. He felt no need to change his accommodations or his home. He stayed in the same lodgings and he returned to the same tent in Beis-El, because his ultimate goal was to return to the same altar, the same mission he had begun, to call out in the name of Hashem. Despite the wealth that he had amassed, he remained focused on his life's mission - to draw people closer to Hashem. The true eved Hashem remains focused on serving Hakadosh Boruch Hu despite whatever else is happening in his personal life.
We find a similar idea later in the parsha. The Torah describes how during the battle of the five kings against the four kings, Lot and the people of Sdom are taken captive, and a fugitive comes to tell Avraham of Lot's plight. Chazal understood that it was Og who escaped from the battle and approached Avraham. The Targum Yonason elaborates on the words of the posuk and explains, "He came on erev Pesach, and he found him (Avraham) as he was making matzos." This is alluded to as well in the Midrash Rabba (42, 8): "Why was he called Og? Because he came and found Avraham involved in the mitzvah of matzos (ugos)."
Why did Chazal highlight this fact that Avraham Avinu was baking matzos when Og came to his tent? I once heard that perhaps Chazal meant to underscore Avraham's dedication to avodas Hashem. It is highly unlikely that Avraham did not know of the war raging between the kings. This was the first world war in history, and people were passing by Avraham's tent on a daily basis. Surely at least one of them would have told him about the war. And yet, what is Avraham preoccupied with? Baking matzos. Avraham fulfilled all the mitzvos of the Torah even before it was given (Kiddushin 82a). Despite whatever else was happening in the world on erev Pesach, Avraham Avinu was involved in baking matzos.
Chazal say (Shabbos 31a) that one of the questions that a person is asked in the heavenly court is "Kavata itim l'Torah - did you have set times for the study of Torah?" One is not asked whether he studied Torah, but rather whether he had set times for the study of Torah. Why is having set times so important? Rashi explains that a person must have some form of livelihood because "im ein derech eretz ein Torah - if one does not have an occupation there is no Torah" (Avos 3:17). Therefore, one must have set times for Torah study so that he will not be drawn to his occupation the entire day. Without having set times, one can easily forget to study Torah because he will be so involved in his work.
In a sense, then, the real question that a person is asked in the heavenly court is not whether he studied Torah during his lifetime, but whether he had a proper sense of priorities. Did you have set times for the study of Torah that were sacrosanct, that you would not sacrifice no matter what was going on in the office, or did you learn Torah only when it worked out with your schedule? Were you able to focus on talmud Torah despite whatever else was happening in your life or were you distracted by your other responsibilities?
Avraham Avinu is a model of a true eved Hashem. No matter what happened to him personally or what world events were transpiring during his lifetime, he always remained focused on serving Hashem to the best of his ability and bringing honor to Hashem's name in all of his endeavors. It is a model worth emulating.