What does Matthew 13:29 mean?

As part of a parable (Matthew 13:24–28), a farmer's servants have asked if they should pull out unwanted plants. They have discovered weeds, called darnel or tares, growing alongside the wheat. Since this inedible ryegrass resembles wheat plants early in the growth cycle, the sudden appearance of so many weeds was an unwelcome surprise. After the master explains that an enemy has done this to them, the servants want to know if they should get to work and pull up all the weeds.

The master now tells them no. Had there been only one or two small plants, or a scattering of them, weeding would have been the simplest solution. This was not a natural problem, however—this was an attack (Matthew 13:25). There would have been many, many weeds intermixed with the good plants. By this stage of development, when the plants can be distinguished, the roots of the weeds would have been entangled with the roots of the wheat. Pulling up that many weeds could destroy the good grain before it is ready to harvest. So, the master will present a better strategy (Matthew 13:30).

Parables are stories meant to summarize larger ideas about the kingdom of heaven. Jesus intends for His disciples to understand these truths, so He will explain exactly what those are later (Matthew 13:36–43).