Jesus explains that until His return, good and evil will grow together in the world. Rather than rushing to judge, God patiently waits until the final harvest, when He alone will separate the righteous from the wicked.
Jesus compares the Kingdom of Heaven to a farmer scattering seed. While the seed is always good, the harvest depends on the condition of the soil. Likewise, God's Word bears fruit in hearts that are receptive, obedient, and willing to follow Him.