"Myth" might not be the right term. But at least there is a misunderstanding. I am talking about an improper view of the Parable of the Sower in Matthew 13:1-23. There are similar accounts of this parable in both Mark and Luke.
It is a story Jesus told about a man who sowed seeds in four kinds of soil. The wayside soil was that which never received the seed (the word of God). The stony ground received the seed, but because the seed did not take good root it withered when the sun beat down on it. The thorny ground received the seed, but the thorns choked it out so that no fruit was born. And, finally, the good ground received the seed and it prospered, producing fruit.
These four soils represent four kinds of hearts that are exposed to the gospel--the seed of the kingdom.
The common view is that the first heart never received the word of God. That is correct. This view continues by concluding that the stony ground represents the person who receives God's word, but in time of persecution falls away. They quit on Jesus; they leave the church. That, too, is correct.
Then, when it comes to the third heart--the soil with thorns--the thorns choke out the word of God, and that person also falls away. The view is that they, like the stony ground heart, fall away, quitting on Jesus and His church. That is the myth! But the text never says they quit. Rather, it says, he "becomes unfruitful" (Matthew 13:22; Mark 4:19), they "bring no fruit to maturity" (Luke 8:14).
There is no indication that the person represented by the third soil (heart) quits the church. Though it is believed by some folks that, indeed, they have quit.
This person may show up at most of the services. Because of his attendance he may be regarded by the church as a "faithful member." But the problem is, he bears no fruit. He may continue to live pretty much the same kind of life he lived before he obeyed the gospel; he does not bear the fruit of the Spirit (Galatians 5:22-24). He brings forth no fruit that shows his repentance (Matthew 3:8). He may not even bear fruit with his lips, because he doesn't sing (Hebrews 13:15); he may just sit there as others sing.
His connection with this world prevents him from being what God truly wants him to be (Matthew 13:22). But he does warm a seat in the meeting house! And, for that, he is deemed a faithful Christian. Rather sad, don't you think?