Midrash sur Isaïe 40:4

... Another explanation. “When the Lord, your God, expands your boundary…” (Deuteronomy 12:20) The Rabbis say: this is speaking of Jerusalem. Who is able to see the calm of Jerusalem when the Holy One expands it? R’ Shimon bar Nachman says: to what is this to be compared? To a country, etc. “And then the offerings of Judah and Jerusalem shall be pleasant to the Lord, as in the days of old and former years.” (Malachi 3:4) “Lo, I will send you Elijah the prophet before the coming of the great and awesome day of the Lord, that he may turn the heart of the fathers back through the children, and the heart of the children back through their fathers-lest I come and smite the earth with utter destruction.” (Malachi 3:23-24) Behold I send My angel and he will clear the way before Me. And suddenly the Master whom you desire will come into His palace and the angel of the covenant whom you desire, behold he is coming says the Lord of Hosts. “Therefore, so said the Lord: 'I have returned to Jerusalem with mercy; My house shall be built there,' says the Lord of Hosts. 'And a plumb line shall be stretched out over Jerusalem.' Further, proclaim, saying: so said the Lord of Hosts, 'My cities shall yet spread out with prosperity, and the Lord shall yet console Zion and shall yet choose Jerusalem.'” (Zechariah 1:16-17) “Be exceedingly happy, O daughter of Zion; Shout, O daughter of Jerusalem. Behold! Your king shall come to you. He is just and victorious; humble, and riding a donkey and a foal, the offspring of she-donkeys.” (Zechariah 9:9)

R. Mathna said: "What is meant by the passage (Num. 21, 18.) And from the wilderness of Mathanah, i.e., if a man makes himself as a wilderness, upon which everybody treads, his learning will endure with him; otherwise his learning will not endure with him." Raba, the son of R. Joseph b. Chama was not on good terms with R. Joseph. Upon the approach of the Day of Atonement, Raba said: "I will go and appease him." So he went to R. Joseph, and found R. Joseph's attendant preparing a cup of wine for his master. "Give it to me and I shall prepare it," said Raba to the attendant. The latter gave the cup to Raba who prepared the wine. As soon as R. Joseph tasted it, he said: "This prepared wine tastes just as if it were prepared by Raba, the son of R. Joseph b. Chama." "It was I who prepared it" explained Raba. R. Joseph then said to Raba: "I shall not permit you to sit down unless you will explain to me the meaning of the following passages (Ib. ib. ib.) And from the wilderness to Mathanah, And front Mathanah to Nachaliel; and from Nachaliel to Bamoth. And from Bamoth to the valley. Raba said to him: "[This means that] if a man make himself just as the wilderness upon which everybody treads, the Torah will be given to him as a gift. Since the Torah was given to him as a gift, the Torah will remain with him as an inheritance, as it is said and from Mathanah to Nachaliel. Since the Torah will remain with him as an inheritance, he will rise to distinction, as it is said and from Nachaliel to Bamoth. But if he exalt himself [with his learning] the Holy One, praised be He! will lower him, as it is said and from Bamoth to the valley; and if he reconsiders his conduct the Holy One praised be He! will raise him again, as it is said (Is. 40, 4.) Every valley shall be raised."

(Fol. 55) Samuel said again: "What does the passage (Num. 218). And from the wilderness of Mathanah to Nachaliel; and from Nachaliel to Bamoth, mean? This means that if a man make himself just as the wilderness upon which everybody treads, the Torah will be given to him as a gift. Since the Torah was given to him as a gift, the Torah will remain with him as an inheritance, as it is said and from Mathanah to Nachaliel. Since the Torah will remain with him as an inheritance, he will rise to distinction, as it is said and from Nachaliel to Bamoth. But if he exalt himself [with his learning] the Holy One, praised be He! will lower him, as it is said and from Bamoth to the valley; and if he reconsiders his conduct the Holy One, praised be He! will raise him again, as it is said (Is. 40, 4) Every valley shall be raised."