Paul in Galatians 6:9 commands Christian’s to do three things:
1: We are commanded to act - note that it is a shared action, as Paul includes himself using "we" and "us".
2. The command is to do good. It’s not a command to look good or to make ourselves good, but it involves doing good for Christ, and therefore involves other people. The 'doing good' is what brings treasure into heaven as Jesus commanded. The 'good' must be practical actions by believers.
3. Paul commands us not to let weariness get us down. It’s very easy to see the rapid declension of the world, it’s hatred for anything good, and beautiful, and pleasant. But Paul encourages us not to grow weary. The method is to look forward. The most difficult task of a long distance runner is to remain focussed and comprehend that he or she will reach the finishing line, although he or she cannot see it. They therefore, cannot focus on the weariness, but the prize at the end. Paul uses running in some of his examples for this very purpose. A farmer cannot give up as he battles with the land and weather and pests and markets to bring forth a crop, but must lift his eyes to the end, even if he cannot see it – because in ‘due season’ he will reap the crop.
Do not lose heart. We need to be in constant communion with the Father, else we will lose heart - the world will make us weary (therefore, we need to wash each other’s feet to help alleviate the weariness). Losing heart has lost many a faithful Christian to self-pity and hopelessness. Our future is with Christ, and like a marathon runner; the end we cannot quite see, but we surely know it’s there.