The parable of the four different types of soil is found in Matthew 13:1-23, Mark 4:1-20 and Luke 8:4-18. There are some common and different details in each version. A comment unique to Mark’s account is Jesus statement about the importance of this parable. A group of His followers asked Him to explain the parable, which He did, and then asked them a question.
13 And He said to them, “Do you not understand this parable? How then will you understand all the parables?” Mark 4:13 (NKJV)
This is a wineskin comment. Jesus was letting them, and by extension us, know that there is a significant principle in the parable of the sower that unlocks truth in the other parables. The principle Jesus was communicating is often presented as the idea of sowing and reaping. While I believe this is inherent in the parable I believe Jesus was communicating something more significant. I call this The Principle of Purpose. In Mark the parable of the sower is followed by the lamp on a lampstand, the need to pay attention to how we hear and two more parables. One about sowing and reaping regarding the power inherent in seeds and the second the parable of the kingdom being like a mustard seed.
I believe Jesus is saying in each of these there is a Principle of Purpose. In the Parable of the Sower, there is purpose connected to the seed and the soil. Jesus is clear that the seed is His word and the soil is our hearts. Isaiah says His word will not return void (Is. 55:11). It will accomplish the purpose for which it was intended. The key to our fruitfulness is not the quality of the seed, the seed is good. Fruitfulness is connected to the quality of the soil, our hearts.
If we want to see good fruit then we need to embrace our responsibility to prepare the soil. Solomon highlighted the importance of good soil in a number of places. Two examples are below.
23 Keep your heart with all diligence, For out of it spring the issues of life. Proverbs 4:23 (NKJV)
1 The preparations of the heart belong to man, But the answer of the tongue is from the LORD. Proverbs 16:1 (NKJV)
It is clear that our hearts are designed to receive His word and outwardly produce the fruit of His inward work in our lives. We are called to live in and from His presence and release truth, life and hope wherever we go. When we do our heart is accomplishing the purpose for which Jesus designed it.