Jesus interpreted His first parable to help His disciples understand it and the others that followed (cf. Mark 4:13).
13:18 Since former prophets and righteous people wanted to know this revelation and since the unbelieving could not understand it, the disciples needed to listen to it carefully.
13:19 Some people heard Jesus' preaching about the kingdom, but, as hard soil, the truth did not penetrate them. Satan snatched the message away before they really understood it. The four soils represent four types of reception people gave the preaching about the kingdom.
13:20-21 The second type of soil stands for those whose initial response to the message Jesus preached was enthusiastic reception. This reception gave hope for much fruit to follow. However external pressures inhibit growth, and because they do not have an adequate rooting in the truth they soon fade and wither (cf. 5:29). These people are disciples who begin well but fail to continue to follow the Lord faithfully. Whether they are saved or lost is beside the point.
"It is important to understand the explanation of the parable of the soils in its context and with the purpose of the original parable particularly in mind. The key issue is responsiveness or non-responsiveness to the message of the kingdom."539
13:22 This disciple allows the other concerns of life to crowd out his commitment to Jesus. He permits the competing concerns of life to take precedence over his spiritual development. The present life rather than the life to come, and present treasure rather than future treasure, capture his affections. They are deceitful in that they can drain spiritual vitality before the person realizes what is happening to him or her.540
13:23 The good soil stands for the person who understands the message about the kingdom when he or she hears it and responds appropriately to it. This would involve believing in Jesus. Such a person eventually becomes spiritually productive, though the degree of productivity varies. However, Jesus commended all who received the message of the kingdom and believed it regardless of their measure of productivity. The fruit in view probably represents increasing understanding of and proper response to divine revelation in view of the context.
If the disciples understood this parable, they could understand the others that followed.
"The principle taught by the parable is this: reception of the word of the kingdom in one's heart produces more understanding and revelation of the kingdom."541
