The early church had multiple problems, many of which Paul and other New Testament writers refer to. Any reasonable person would have taken these problems as a sign that the faith they were pushing really didn’t work; didn’t produce new creations powered by a holy spirit. Some, including a number of the very earliest followers (Matthew 28.17), were leaving the church, disappointed and disillusioned. How were leading figures in the cult to explain this? Having supposedly encountered the supernatural Jesus these people were now having doubts that he was real and were turning their backs on him. This shouldn’t have been happening!
The writer of 1 John accounts for the departure of those who had come to their senses by suggesting they were never really true believers:
They went out from us, but they were not of us; for if they had been of us, they would have continued with us. But they went out, that it might become plain that they all are not of us. (1 John 2:19)
It’s significant that the writer of this letter doesn’t allude to Jesus’ parable about the sower of the seeds from Matthew 13. Not one of the letter writers in the New Testament who address the problem of defections does so. This can only be because none of them knew of it when they were writing decades after it was supposedly told. The reason they don’t mention it is because it had yet to be written.
The parable of the sower is Matthew’s attempt to have Jesus address the problem of those who fell away from the cult. Matthew’s explanation is it’s because the good news – the imminent arrival of God’s kingdom on Earth – only takes root in the spiritually astute. Others, who might initially accept the gospel, are like stony ground on which birds gobble up the seed. They are those who allow the cares of this world – metaphorical weeds – to choke the message before it can flourish.
It’s a very colourful explanation designed to reassure those persisting in the faith that they are the favoured, while those who have defected have fallen prey to the shallow soil, birds and weeds. It’s neat and it gives reassurance and encouragement to remaining cultists.
Jesus could not possibly have known what was to become of his ‘church’ and the (non)arrival of God’s Kingdom – his good news – following his death. The parable was created for him, or more specifically, as Matthew makes abundantly clear in 13:11-12, for devotees of the early cult decades later. What it emphatically is not, is a story originally delivered by Jesus.