The Parable of the Leaven, also called the parable of the yeast, is one of the shortest parables of Jesus. It appears in Matthew 13:33 and Luke 13:20–21, as well as in the non-canonical Gospel of Thomas. In the canonical gospels it immediately follows the Parable of the Mustard Seed, which shares this parable's theme of the Kingdom of Heaven growing from small beginnings. In the Gospel of Thomas it starts a series of three, preceding the Parable of the empty jar and the Parable of the Strong Man.

In Judaism, the Holy Spirit, otherwise known as the Holy Ghost, is the divine force, quality and influence of God over the universe or his creatures. In Nicene Christianity, the Holy Spirit is the third person of the Trinity. In Islam, the Holy Spirit acts as an agent of divine action or communication. In the Baha’i Faith, the Holy Spirit is seen as the intermediary between God and man and "the outpouring grace of God and the effulgent rays that emanate from His Manifestation".