1. Parables of the kingdom 13:18-21

The connection with what has preceded that Luke's "therefore"suggests is probably the reaction of the multitude (v. 17). Since the multitude reacted positively to Jesus, He taught them about the coming messianic kingdom. His previous comments about coming judgment made this teaching appropriate.

These parables occur in Matthew and Mark in a different context. Luke therefore may have reported the same teaching on another occasion, or he may have moved Jesus' teaching on the occasion Matthew and Mark reported to this place in his Gospel. The former alternative seems more probable.

 The parable of the mustard seed 13:18-19 (cf. Matt. 13:31-32; Mark 4:30-32)

The kingdom of God is the messianic kingdom that the Old Testament predicted. It would be an earthly kingdom over which Messiah would rule for 1, 000 years (Rev. 20:4-6). It is similar to a mustard seed in that it had a small beginning in the preaching of Jesus, but it will grow to be a very large entity. It will eventually encompass the whole earth and the entire human race (Ps. 2; et al.).

The reference to the birds nesting in its branches may simply be an insignificant detail. However it is probably an allusion to the tree in Nebuchadnezzar's dream in which the birds evidently represent the Gentile nations that profit from the tree (kingdom, Dan. 4:7-23). Several Old Testament passages use a tree with birds flocking to its branches to illustrate a kingdom that people perceive as great (Judg. 9:15; Ps. 104:12-13; Ezek. 17:22-24; 31:3-14).

The point of the parable is the growth of the kingdom from a very small and apparently insignificant beginning to a very large entity. Particularly its small beginning is in view. In this context Luke probably wanted his readers to connect the great power of Jesus manifested in the woman's healing (vv. 10-17) and the power that results in the tree's unusual growth.

 The parable of the yeast hidden in meal 13:20-21 (cf. Matt. 13:33)

Jesus' similar introduction of this parable (cf. v. 18) suggests a similar point, but the fact that He gave a different parable implies a slightly different emphasis. Obviously the pervasive growth idea is present in both parables, but the second parable stresses the hidden nature of the growth more than the first one did. The idea of power for growth also carries over.