Galatians 6:9

Let us not become weary in doing good, for at the proper time we will reap a harvest if we do not give up.

(v9, NIV)

It's very easy to grow weary doing good. The work of a farmer is very tiring work. It's not just about planting the seeds, but tending the garden. In order for the seeds to produce good fruit, the soil needs to be prepared and the plants need to be watered. Plants require trimming and pruning in order to produce the best results. I can't say this first hand, but the work of a farmer sounds like very tiring work. As followers of Christ, we are to sow spiritual things. Sowing spiritual things from the Spirit will reap everlasting life. This is contrasted with sowing to the flesh, which reaps corruption.

It is tempting to simply give up when things get tough. However, do not give up. Eventually, we will reap what we harvest. Do not give up doing good or sowing spiritual things. If we persevere, we will reap eternal life.