Matthew 13:3

And he spake many things unto them in parables, saying, &c.--These parables are SEVEN in number; and it is not a little remarkable that while this is the sacred number, the first FOUR of them were spoken to the mixed multitude, while the remaining THREE were spoken to the Twelve in private--these divisions, four and three, being themselves notable in the symbolical arithmetic of Scripture. Another thing remarkable in the structure of these parables is, that while the first of the Seven--that of the Sower--is of the nature of an Introduction to the whole, the remaining Six consist of three pairs--the Second and Seventh, the Third and Fourth, and the Fifth and Sixth, corresponding to each other; each pair setting forth the same general truths, but with a certain diversity of aspect. All this can hardly be accidental. First Parable: THE SOWER (Mat 13:3-9, Mat 13:18-23). This parable may be entitled, THE EFFECT OF THE WORD DEPENDENT ON THE STATE OF THE HEART. For the exposition of this parable, see on Mar 4:1-9, Mar 4:14-20. Reason for Teaching in Parables (Mat 13:10-17).

— Jamieson-Fausset-Brown Commentary (public domain)