"He gives power to the weak and strength to the powerless. Even youths will become weak abd tired, and young men will fall in exhaustion. But those who trust in the Lord will find new strength. They will sour high on wings like eagles. They will run and not grow weary. They will walk and not faint." Isaiah 40:29-31 (NLT)
The promise God provides is that even if you get weary, He will provide the people that follow Him the strength to keep going. It is more than that. He promises you to feel younger than you are to be able to endure and it not be hard at times. The strength that God gives you is powerful. If you refuse to follow Him in faith, then you will grow weary and give up over time no matter how young you may be.
There is no end to God's power. When He lays just a little upon you will feel like you will never be weak, tired, weary, or touched by evil again. If you rely upon your own strength, then you will find out what your limits are quickly. You can not succeed in the long game without God. You have to put your trust in Him and His plans for your life.
This is encouraging because you can access His strength at any time. You do not have to rely on your limited strength, knowledge, or wisdom. He will give you what you need. He will give it to you as much as you need it to fulfill your purpose in this world. A season of waiting is not a punishment. It is an opportunity to get strong and prepare for what is to come. A season of rest is a gift to make you stronger. When you work with God you can do anything, even wait.
When you feel like you have nothing left to give turn all those feelings over to God. Pray for rest, the cobwebs to be cleared, and how to move forward. There is no need to keep pushing forward. It will only cause more harm than good to you and your ministry. You have to rely on God and take direction from the Holy Spirit as it is given to you to avoid burnout. It can take years to recover from burnout, so avoid it when you can. Allow God's peace to work within you.
Psalm 29:11, 103:5, 138:3, Isaiah 40:29-31, Lamentations 3:25-27, 2 Corinthians 12:9-10, & Philippians 4:13