After Jesus gave the parable of the sower in which He described the word of God being sown as a seed in the hearts of men (Mark 4:3-9, 14-20), He told another parable similar to this. “And He was saying, ‘The kingdom of God is like a man who casts seed upon the soil; and he goes to bed at night and gets up by day, and the seed sprouts and grows—how, he himself does not know’” (Mark 4:26-27).
In this parable, like the parable of the sower, Jesus described the word of God being planted as a seed. In other words, someone was going out and preaching the gospel. However, after he put forth the effort to teach and went away, only then did the seed begin to grow. The one who planted did his work. Fretting over whether or not it would take root and grow would not help.
So it is with our efforts. We need to spread the gospel and plant the seed in the hearts of others. Yet often we will not see any visible growth. However, this does not mean we should become discouraged. Instead, we need to be content with our best efforts and trust in God to give the increase (cf. 1 Corinthians 3:6).
So remember that we will never know the full impact of our efforts. Let us continue to spread the word and point people to the Lord. As we do this, we can “[go] to bed at night” and rest with the assurance that we have done what we could and trust that the word of God will work as He intended.