Jude 1:3

Beloved, while I was very diligent to write to you concerning our common salvation, I found it necessary to write to you exhorting you to contend earnestly for the faith which was once for all delivered to the saints.

Mark 4:30-32

Then He said, “To what shall we liken the kingdom of God? Or with what parable shall we picture it? It is like a mustard seed which, when it is sown on the ground, is smaller than all the seeds on earth; but when it is sown, it grows up and becomes greater than all herbs, and shoots out large branches, so that the birds of the air may nest under its shade.”