Or HaChaim on Deuteronomy 11:13/אור החיים על דברים י״א:י״ג

1 והיה אם שמע תשמעו, "and it will be if you will surely hearken, etc." The meaning of the word והיה is usually that something joyful will occur. Moses tempers this by making the joy conditional on it being due to performance of G'd's commandments. Moses continues with the conditional אם [as opposd to the word כאשר "when," Ed.]. The reason is analogous to what we have learned in Shabbat 30 that the only kind of joy Solomon praised was the joy generated through מצוה-performance. Concerning all other kinds of joy Kohelet 2,2 applies, i.e. ולשמחה מה זה עושה, "and of joy, what does it accomplish?" Moses repeated the word שמע based on a comment in Berachot 55 on Daniel 2,21 "He gives wisdom to the wise and knowledgable." G'd does not grant wisdom unless a person has already acquired a measure of wisdom. When Moses says: "if you will hearken" he means if you already have a wise heart and are mentally prepared to hearken, G'd will grant you more such wisdom so that you will surely hearken to G'd."

2לאהבה…ולעבדו…ונתתי, "to love G'd..to serve Him;..and I will give the rain, etc." In view of previous statements to the effect that the reward for מצוה-performance is not paid in this life, Moses assures the people if their service is of a quality that is equivalent to their loving G'd with all their heart then they will also experience compensation in this life. This is the meaning of the conjunctive letter ו at the beginning of the word ונתתי in verse 14. Receiving rainfall at the appropriate time is not the reward for their מצוה-performance but is something additional, i.e. ו, plus. The reward itself is stored up for the Hereafter. Moses also hints that although a good livelihood is one of the three blessings which are within the province of mazzal and not of personal merit as we explained repeatedly (Moed Katan 28), when the nation serves the Lord in the above-mentioned manner Israel as a whole will rise above mazzal and everything which happens to it comes under the scrutiny of the personal providence of G'd.

3בכל לבבכם ובכל נפשכם, "with all your hearts and with all your souls." In this instance Moses did not mention מאדכם, "your material assets" as he did in Deut. 6,5. The reason is that the paragraph in Deut. 6 was addressed to the individual Jew whereas this paragraph is addressed to the nation as a whole. Whereas it is possible to find an individual who values his material assets over and above his very life, the Torah had to command that Jew not to do so. Amongst the people collectively it is psychologically impossible to find them value their assets as worth dying for. In such a setting, the rule applies that people will give up all their wealth in order to save their lives. As soon as Moses had told the people that they should love the Lord with all their souls, it went without saying that the same applies to all their material assets.