Midrash su Deuteronomio 15:2

And he called to Moshe: Rabbi Tanchum Bar Chanilai opened (Psalms 103:20), “'Bless the Lord, His messengers (malachav), powerful ones who fulfill His word, etc.' About whom is the verse speaking? If the verse is speaking about the [angels], has it not already been stated, 'Bless the Lord, all of His Hosts?' Behold, it is only speaking about [people]. [About the angels,] since they are able to accomplish the errands of the Holy One, blessed be He, they are told, ' Bless the Lord, all of His Hosts'; but [about people], since they are not able to accomplish the errands of the Holy One, blessed be He, hence it states, 'Bless the Lord, His messengers,' and not 'all of His messengers.'” Another explanation: The prophets are called messengers. So is it written (Numbers 20:16), “and He sent a messenger and he took us out of Egypt.' And was it an angel of the Lord, and was it not Moshe? And [so] why is he called a messenger? Rather, from here [we see that] prophets are called messengers. And like it is (Judges 2:1) “And a messenger of the Lord came up from Bokhim.” Was it an angel of the Lord and was it not Pinchas? And [so] why did it call him a messenger? But rather Rabbi Simon said, “When Pinchas had the holy spirit come upon him, his face would burn like torches.” And our rabbis said, “Manoach's wife said to him (Judges 13:16), 'Behold, a man of God is coming towards me and his appearance is like the appearance of an angel of God' – she thought that he was a prophet and he was [actually] an angel.” Rabbi Yochanan said, “From their essence, the prophets were called messengers – so it is written (Chaggai 1:13), 'And Chaggai, the messenger of the Lord in the service of the Lord said.' Perforce you learn that from their essence, prophets were called messengers.” (Psalms 103:20) “Powerful ones who fulfill His word, etc.” – about what is the verse speaking? Rabbi Yitzchak said, “The verse is speaking about those that observe the sabbatical year. It is customary in the world that a man will fulfill a commandment for a day, for a Shabbat, for a month, but for the rest of the days of the year? And this one watches his field empty, watches his vineyard empty and he gives his purse and is silent – is there one more powerful than this one? And if you would say that it is not speaking about those that observe the sabbatical year, here it states, 'who fulfill his word' and later it states (Deuteronomy 15:2) 'This is the word of the Sabbatical.' Just like regarding the word that is stated later on, the verse is speaking about those that observe the Sabbatical year, so too the word stated here, - it is about those that observe the Sabbatical year that the verse is speaking. "Who fulfill His word" - Rabbi Huna said in the name of Rav Acha, "The verse is speaking about Israel when they were standing in front of Mount Sinai; as they had fulfilling precede hearing and said (Exodus 24:7), 'Everything that the Lord said, we will fulfill and we will hear.'" [The verse in Psalms continues] "To listen to the voice of His word" - Rabbi Tanchum Bar Chanilai said, "It is customary in the world that a load that is difficult for one [to carry] is comfortable for two, and [one difficult] for two is comfortable for four; and [so] would a load that is difficult for sixty multitudes be comfortable for one? All of Israel was standing in front of Mount Sinai and saying (Deuteronomy 5:22), 'if we continue to listen, etc.' and [yet] Moshe listens to the Voice of the word by himself and lives? You should know that it is so, as from all of them He only called to Moshe. Hence it states, 'And He called to Moshe.'"

6) (Vayikra 25:13) "In the year of this Yovel you shall return a man to his possession." "This" (i.e., Yovel) grants bondsmen their freedom, but not shevi'ith. (For without this verse) it would follow otherwise, a fortiori, viz.: If Yovel, which does not release money (i.e., debts), releases bondsmen, then shevi'ith, which does release money, how much more so should it release bondsmen! It must, therefore, be written "In the year of this Yovel, etc." — This (Yovel) releases bondsmen, but not shevi'ith. — But let it follow a fortiori that Yovel releases money, viz.: If shevi'ith, which does not release bondsmen, releases money, then Yovel, which does release bondsmen, how much more so should it release money! It is, therefore, written (Devarim 15:2): "And this is the word of the shemitah, every creditor shall release, etc." — Shevi'ith releases money, but Yovel does not release money. "you shall return a man to his possession": to include a field dedicated to the sanctuary, which was redeemed by his son, as returning to his father on Yovel.

(Devarim 15:2) "And this is the word of the shemitah": From here it was ruled: If a debtor returns his debt in the seventh year, the creditor must tell him: "I release it."