Why did egytians leave the heart in body?

Ancient Egyptians believed that the heart was the center of intelligence, emotion, and personality, and that it would continue to function after death. They believed that the person's heart would be weighed against the feather of Ma'at, the goddess of truth and justice, to determine whether they were worthy of entering the afterlife. If the heart was lighter than the feather, the person would be allowed to enter the afterlife, but if it was heavier, they would be condemned to eternal punishment.

For this reason, Egyptians took great care to preserve the heart during mummification. The heart was left in the body, and the lungs and other organs were removed and placed in jars. The heart was then coated in natron, a salt that helped to preserve it, and it was wrapped in linen bandages. In some cases, the heart was even removed from the body and placed in a separate jar.