Midrash Assereth Hadibroht.
There are three things which a man does not wish for: Grass to grow up among his grain-crops; to have a daughter among his children; or that his wine should turn to vinegar. Yet all these three are ordained to be, for the world stands in need of them. Therefore it is said, “O Lord, my God, Thou art very great!... He causeth the grass to grow for the cattle” (Ps. civ. 1, 14)
Midrash Tanchuma.
There are four cardinal points in the world, etc. The north point God created but left unfinished; for, said He, “Whoever claims to be God, let him come and finish this corner which I have left, and thus all will know that he is God.” This unfinished corner is the dwelling-place of the harmful demons, ghosts, devils, and storms.
Pirke d’Rab. Eliezer, chap. 3.
A Min once asked Rabbi Akiva, “Who created this world?” “The Holy One—blessed be He!”—was the reply. “Give me positive proof of this,” begged the other. “Come to-morrow,” answered the Rabbi. On coming the next day, the Rabbi asked, “What are you dressed in?” “In a garment,” was the reply. “Who made it?” asked the Rabbi. “A weaver,” said the other. “I don’t believe thee,” said the Rabbi; “give me a positive proof of this.” “I need not demonstrate this,” said the Min; “it stands to reason that a weaver made it.” “And so thou mayest know that God created the world,” observed the Rabbi. When the Min had departed, the Rabbi’s disciples asked him, “What is proof positive?” He said, “My children, as a house implies a builder, and a garment a weaver, and a door a carpenter, so likewise the existence of the world implies that the Holy One—blessed be He!—created it.”
Midrash Terumah.
When the Holy One—blessed be He!—created the world, it was a level expanse free from mountains; but when Cain slew Abel his brother, whose blood was trodden down on the earth, He cursed the ground, and immediately hills and mountains sprang into existence.
Midrash Vayosha.