EXTRA · Parashas Reeh · Third Aliyah · Passuk 13:19
Supplementary classical material for a passuk with no Torah Temimah citation.
English: “And He will grant you mercy and have mercy upon you and multiply you” — from here Rabbi Shimon ben Gamliel said: Whoever has mercy on creatures receives mercy from Heaven, and whoever does not have mercy on creatures does not receive mercy from Heaven. “And multiply you” — as it is said, “And I will multiply your offspring like the stars of heaven.” “As He swore to your fathers” — all of it is through the merit of your fathers. “When you hearken to the voice of Hashem your God” — from here they said: If a person begins to hearken a little, eventually he is caused to hear much. “To keep all the commandments” — that a light commandment should be beloved to you like a weighty commandment. “To do what is right” — in the eyes of Heaven.
Derash on the conditional close (Sifrei) — the blessing after the herem depends on ongoing obedience.
After the destruction of an apostate city, the promise of mercy and increase is contingent on continued hearkening and doing what is right.