{As it is stated:} (Exodus 34:28) "And he was there with the LORD…." There was an incident with Rabbi Yochanan, who went from Tiberias to Sepphoris, and Rabbi Chiyya bar Abba, his disciple, was with him. The two of them were walking along the road, and Rabbi Yochanan saw a vineyard, and he said to Rabbi Chiyya: "This was mine, and I sold it for such-and-such." And likewise an olive field was mine, and I sold it for such-and-such. Rabbi Chiyya said to him: "And of all the estate (that is, the fields), did you not have anything to leave for your old age?" He said to him: "I sold something worth six gold coins, and I acquired something worth forty gold coins." He said to him: "And what did you acquire?" He said to him: "I sold a thing—fields and vineyards—that were created in six days, and I acquired Torah, which was created in forty days."
Rabbi Yochanan Sells His Fields to Acquire the Torah
Midrash Tanchuma Buber, Ki Tisa 19:2
(שנאמר) ויהי שם עם ה' וגו' (שמות לד כח). מעשה היה בר' יוחנן שהלך מטבריא לצפוריוהיה ר' חייא בר אבא תלמידו עמו, והיו שניהן מהלכין בדרך, והיה ר' יוחנן רואה כרם, והיה אומר לר' חייא זו היתה שלי, ומכרתי אותה בכך, וכן שדה זיתים שלי היתה, ומכרתי אותה בכך, א"ל ר' חייא ומכל האוסייה (פי' השדות) לא היה לך להניח בזקנותך, א"ל מכרתי דבר ששוה ו' זהובים, וקניתי דבר ששוה מ' זהובים, א"ל ומה לקחת, א"ל מכרתי דבר שדות וכרמים שנבראו לו' ימים, וקניתי תורה שנבראת למ' יום.