Sforno on Deuteronomy 6:3/ספורנו על דברים ו׳:ג׳

1ושמעת ישראל, when you have attained this purpose which G’d had had in mind for you from the beginning in His great kindness. It is important that through performance and awareness you will appreciate the tremendous goodwill G’d has demonstrated by His legislating these commandments.

2ושמרת לעשות אשר ייטב לך, and you will endeavour to carry out all these tasks out of a feeling of love for G’d, in order to be worthy of His goodwill, aware that He is interested in creating conditions which will make you merit a continued existence. Seeing that this is His purpose in legislating any and all of these commandments, you will also observe these commandments in order to multiply greatly on earth. This is a goal you will achieve if your performance of these commandments is not for the sake of the material reward but לשמה, for His honour, as acts of righteousness and justice in the pure sense. כאשר דבר ה' אלוקיך לך, ארץ זבת חלב ודבש, as He had said to you concerning this land that it “flows with milk and honey.” This land is inherently capable of providing those of its owners who take the lesson we just spelled out to heart, with an easy livelihood, a livelihood which leaves the person sufficient leisure time to pursue Torah studies and by means of this to penetrate more deeply into its meaning and also to be fruitful and to multiply.