Of all the parables, the one that opens the series of kingdom parables is the parable of the Seed, better called the parable of the soils. The major point I want to make about this passage is that it lists the obstacles to responding to the Word that ought to be avoided. So attachment to this world or persecution can become an obstacle to receiving the Word. Those are the major obstacles. Beyond this, it takes a patient and persevering heart to make "good" soil.