Referring to the parable of the sower, Craig Blomberg comments,
Many readers have wondered how to fit these four categories of individuals into the two categories into which Jesus has already made clear everyone falls (cf. 7:13–27; 10:32–42). The answer is actually fairly straightforward. The first three kinds of soils are all inadequate. None of them stands for people who were ever true believers, despite certain outward appearances. For farmers, only those plants that bear good fruit (“produced a crop,” v. 8) count for anything. True believers are thus only those who bear proper spiritual fruit (7:16–17). Of the rest Jesus says, “I never knew you” (7:23). What counts is not profession of faith but perseverance in faith. To be sure, all true Christians will persevere, but only by observing who perseveres can we determine who those true Christians are. Matthew’s climactic focus, however, remains on the astonishing impact of those who are faithful. Jesus provides his followers with an important reminder of God’s continued blessings on their work, even as large numbers of people become increasingly hostile to the gospel. He will make this point again in vv. 31–33. NAC Matthew commentry. pp. 214–215.