Musar for Chullin 177:5

They further said (Chulin 89a): "'It was not because you were greater than any people that the L-rd desired in you and chose you' (Devarim 7:7) - the Holy One, blessed be He, said to Israel, 'My sons, I desire you because even when I bestow greatness upon you, you humble yourselves before Me. I bestowed greatness upon Avraham, yet he said to Me, 'I am but dust and ashes' (Gen.18:27); Upon Moses and Aharon, yet they said: 'And we are nothing' (Ex.16:7); upon David, yet he said: 'I am but a worm and no man' (Tehilim 22:7)"

The Baal HaTurim draws our attention to the opening verse of our פרשה, and compares it with the last verse in the previous פרשה which speaks about performance of the commandments. He arrives at the conclusion that whereas the commandment has to be performed in this life, the reward for its performance, עקב, will have to await the Hereafter. Whereas the Baal HaTurim arrives at the same conclusion as the Talmud in Eruvin 22a where the word היום is stressed as opposed to the מחר, i.e. the Hereafter, when the reward is to be collected, he derives it from a different nuance in the text of the Torah. The reason may be that the Baal HaTurim found some problems with the exegesis of the Talmud. Had the interpretation of the Talmud been correct then all the Torah had to write in 7,11 is the whole verse without the word לעשותם at the end Furthermore, the Torah could simply have written לעשות instead of לעשותם. It seems therefore that the suffix ם is to contrast the difference between לעשותם and לעשותך. The difference between these two wordings is an allusion to the motivation which governs performance of the commandments. The Torah does not want us to perform the commandments for the sake of the eventual reward but לעשותם, for their own sake, i.e. לשמה. The fact that a new פרשה begins with the reference to the reward emphasizes that the reward is a corollary, a consequence of performance, but is not in a relationship of על מנת, "on condition that," to our performance of the מצוה. The humility implied in performance of the commandments on the basis of לעשותם (as we have explained the word) is further underlined by the Torah in 7,7: לא מרובכם מכל העמים .. כי אתם המעט מכל העמים, "It is not because you are the most numerous of all the nations that G–d took a liking to you….indeed you are the smallest of all the nations, etc." There was no need for the Torah to write that we are not the most numerous nation and to follow it up with the statement that we are the smallest nation. The last statement would have sufficed. The Talmud Chulin 89a concludes from this that the Torah's choice of language means that G–d likes us because, even when we are granted importance by G–d, we do not make this a pretext to become haughty, but we deprecate ourselves, behave humbly and modestly, ממעטים את עצמכם. This is reinforced in the lesson that Rabbi Levitas in Avot 4,4 urges us to heed: מאד מאד הוה שפל רוח, "Be exceedingly humble in spirit."