Do you think you would still give up if you knew that success was just around the corner? It is discouraging when you keep working hard but see no results. Paul challenged the Galatians in this verse not to give up and not to get tired of doing what was right, for God would surely reward the right things we did. It's a great reminder for us all to keep in mind today as well. 
The Israelites wandered through the desert for forty years in a brutal environment. What if they had given up after thirty-nine? What if they decided one day that the destination wasn’t worth the trip that it took to get there? They had to persevere. Their willingness to keep going and to keep pushing forward allowed them to reach The Promised Land.
Failure is not the end of the road but a detour. You never know what will happen to you if you listen to the evil and stop trying. You can’t allow a setback to throw you off course or discourage you from trying again. God's timing is perfect. If we keep on doing good and trust God for the results, we will reap a harvest of blessings at just the right time.

Dear Heavenly Father, thank You for Your grace and blessings. I have thought about giving up so many times, but You have always been there to cheer me up and give me hope. I can always find hope in You. Help me to stay positive and encouraged regardless of my circumstances. Help me to never grow weary of doing good to others and doing what brings You glory. 
In Jesus's name I pray. Amen.