Rabbi Yishmael asked: why did Job risk everything by demanding an answer from God (Job 31:35)? Because Job understood something terrible. Without death, life has no name. Without darkness, light cannot be recognized. God created the entire world in pairs, each thing paired with its opposite, each opposite giving the other meaning.
Consider the body. Four elements rule it like four officers over an army: blood, white phlegm, red bile, and black bile. When all four hold their posts, a person lives. When one weakens, the body staggers. When one vanishes entirely, the spirit departs and the flesh expires. "You hide Your face, they vanish" (Psalms 104:29). The body is like an inflated waterskin. Puncture it, and the air escapes. So the spirit flees when any single element fails.
These four elements mirror the four directions of the world. White corresponds to the east, where light is born. Blood corresponds to the north, because the body is open to blood everywhere you cut it, and northerners are ruddy. Red bile matches the west, where the sun reddens as it sets. Black bile belongs to the south, born of coolness and shadow. And the four elements of nature parallel them: earth for black bile, cold and dry. Fire for red bile, hot and dry. Water for white phlegm. Air for blood.
God made light and darkness (Isaiah 45:7). Life and death. Paradise and Gehinnom (the place of spiritual purification after death). Every person is judged by both. And when an unbeliever challenged Rabbi Akiva, demanding proof that God created the world, Rabbi Akiva asked him: "Who made the garment you are wearing?" "The weaver," the man said. "Show me proof," Rabbi Akiva replied. The man sputtered: "Everyone knows a weaver makes garments!" Rabbi Akiva smiled. "And everyone should know that God created the world. Just as a house reveals its builder and a door reveals its carpenter, so the world reveals the One who made it."