The traditional view held that the parables of the Mustard Seed and of the Leaven are about the Kingdom of Heaven coming to progressively fill the whole earth is herein contested.
Matt. 13:31-33 “The kingdom of heaven is like to a grain of mustard seed, which a man took, and sowed in his field: Which indeed is the least of all seeds: but when it is grown, it is the greatest among herbs, and becometh a tree, so that the birds of the air come and lodge in the branches thereof.
Another parable spake he unto them; the kingdom of heaven is like unto leaven, which a woman took, and hid in three measures of meal, till the whole was leavened”.
In the parable of the Mustard Seed, it is a “field” in which a man “took and sowed” the mustard seed, it is NOT the whole earth. In the Parable of the Leaven, the leaven is taken and hidden likewise only in the three measures of meal, it is NOT hidden in everything else. The “field” is that of the Israelites, and the meal is what they are given for food.