Let both grow together until the harvest, and at the time of harvest I will say to the reapers, “First gather together the tares and bind them in bundles to burn them, but gather the wheat into my barn.” (Matthew 13: 30)
When a person sincerely repents of their sins and truly accepts Jesus Christ as their personal Lord and Savior, their salvation is guaranteed. However, their spiritual maturity is not. That is to say, at the point of salvation, a person’s status is instantly changed from lost to saved. It is from this point that Christian growth begins. Just as the salvation is sure, it is also sure that obstacles will invariably arise to stunt or stop continuous spiritual growth after salvation. Here, Jesus suggests that often the main obstacle is the fact that weeds have been sown alongside the good seeds. These weeds compete with the seeds for minerals, water, light and life.
Your normal reaction might be to pull up the weeds. Yet, Jesus says, if you do, you may risk uprooting and killing the good plants as well. His recommendation, therefore, is to let the weeds grow along with the good plants and let God do the separating. What this means for spiritual maturity is that we are not always given the luxury of a perfect patch in which to grow. The best we can do is to keep our direct connection to God as the source of our strength. At the same time, we must watch out for those weeds which try to steal the nutrients we need to grow and be fruitful in Christ.