William Burkitt on Mark 4:30

The design of our Saviour in this parable is to show how the gospel-church, from small and little, from unlikely and contemptible beginnings, should spread and increase, fructify and grow up, like as mustard-seed, one of the smallest of grains, grows up to a considerable tallness; even so Christ foretells that the gospel should spread and increase, nations and countries becoming Christians.

Hence learn, That how small beginnings so ever the gospel had in its first plantation, yet by the fructifying blessing of God it has had, and shall have a wonderful increase.