Midrash su Salmi 29:10

Rabbi Azarya [said] in the name of Rabbi Yehuda that Rabbi Simon said: This is analogous to a king who had an orchard, and they descended and planted a row of fig trees, a row of grapevines, a row of pomegranate trees, and a row of apple trees. He entrusted it to a sharecropper and went. Some time later, the king came and peered at the orchard to ascertain what he had done, and he found it filled with thorns and briars. He brought cutters to cut it down,²¹He was going to cut down the entire orchard. but he saw a rose in it and smelled it, and he was placated. The king said: Because of this rose, the orchard will be saved. So too, the world was created only for Israel. After twenty-six generations passed, the Holy One blessed be He peered at His world to ascertain what it had done, and He saw that it was water in water. The generation of Enosh was obliterated with water.²²See Bereishit Rabba 23:6. The Generation of the Flood was obliterated with water; the Generation of the Dispersion, in water. He brought cutters to cut it, as it is stated: “The Lord sat enthroned at the Flood” (Psalms 29:10).²³He sat in judgment. He saw a rose, this is, Israel; He took it and smelled it when Israel assented to the Ten Commandments, and He was placated. When Israel said: “We will perform and we will heed” (Exodus 24:7), the Holy One blessed be He said: ‘Due to this rose, the orchard will be spared; due to the merit of the Torah and those who engage in its study, the world will be spared.’

Rabbi Azaria in the name of Rabbi Y'hudah son of Rabbi Shimon says: The matter may be compared to the case of a king who had an orchard planted with one row of fig trees, one of vines, one of pomegranates, and one of apples. He entrusted it to a tenant and went away. After a time, the king came and looked in at the orchard to ascertain what it had yielded. He found it full of thorns and briars, so he brought woodcutters to raze it. He looked closely at the thorns and noticed among them a single rose-colored flower. He smelled it, and his spirits calmed down. The king said: "The whole orchard shall be saved because of this flower." In a similar manner, the whole world was created only for the sake of the Torah. . . . God saw a single rose-colored flower, to wit, Israel. God took it and smelled it when God gave them [the Israelites] the Ten Commandments, and God's spirits were calmed when they said, We will do, and we will hear (Exodus 24:7). Said the Holy One, "The orchard shall be saved on account of this flower. For the sake of the Torah and of Israel the world shall be saved." (Vayikra Rabbah 23:3)