The rocky places that do not have much earth signify the heart that is shallow in receiving the word of the kingdom, because deep within are rocks--hidden sins, personal desires, self- seeking, and self-pity--which frustrate the seed from gaining root in the depth of the heart.

The good earth [Matt. 13:23] signifies the good heart that is not hardened by worldly traffic, that is without hidden sins, and that is without the anxiety of the age and the deceitfulness of riches.