Rabbi Aba and Rabbi Yitzchak discuss the witnesses that bear testimony about Yisrael, and we learn that they are the well of Isaac, the lottery, the stone that Joshua placed and the song of praise that God taught Moses just before his death.
21. "Take this book of the Torah, and put it in the side of the Ark of the Covenant of Hashem your Elohim..." (Devarim 31:26). HE WAS ASKED WHY HE SAID, "HASHEM YOUR ELOHIM," RATHER THAN 'HASHEM OUR ELOHIM.' AND HE ANSWERS, we have explained this IN SEVERAL PLACES, THE REASON FOR THE NAMES 'your (plur.) Elohim,' 'your (sing.) Elohim,' 'El,' 'our Elohim.'
22. As Rabbi Aba said in the name of Rabbi Yehuda, what is the meaning of, "for the place on which you do stand is holy ground" (Shemot 3:5)? It is surely holy ground, namely the land of the living, WHICH IS MALCHUT. "On which you do stand:" surely it is on it, that is in the beginning and all the more so later. We learned that Rabbi Yosi said, it is written, "that it may be there for a witness against you" (Devarim 31:26), a witness surely to give testimony.
23. There are three who testify. They are Isaac's well, the lot and the stone, which Joshua placed. And this poem more than all, AS IT SAYS, "THAT THIS POEM MAY BE A WITNESS FOR ME..." (IBID. 19). Rabbi Yitzchak said, in that case there are four. He said to him, surely THIS IS SO, but no testifying is mentioned in relation to the lot.
24. Whence do we know about Isaac's well? From the verse, "that they (it) may be a witness to me" (Beresheet 21:30); about the lot, from the words, "According to the lot shall their inheritance be divided" (Bemidbar 26:56), which used to say, 'this is to Judah,' and 'this is to Benjamin,' and so on. HENCE IT SAID, "ACCORDING TO (LIT. 'BY THE MOUTH OF') THE LOT," WHICH MEANS THE LOT SPOKE. As for Joshua's stone, it is written, "Behold, this stone shall be a witness to us" (Yehoshua 24:27). And here IT IS WRITTEN, "that it may be there for a witness against you," and, "that this poem shall testify against them as a witness" (Devarim 31:21). Surely it testified against Yisrael.