Psalm 27:14 Wait on the Lord: be of good courage, and he shall strengthen thine heart: wait, I say, on the Lord. (KJV)
Waiting on the Lord means to wait in faith after we have made known our petition and requests to Him. God never turns down anyone who goes to Him with faith. When we wait on men for support and strength, we fail. We will most certainly be disappointed when human promises of hope and security fail.
David encouraged himself in the Lord most of the time. Isaiah, the prophet, said those who wait on the Lord would renew their strength like an eagle. So what does that mean? It means that we have to build a strong bond with the Lord Jesus. As we wait in the Lord’s presence through prayer and faith, our inner man keeps deriving the required strength to face the world. The more we pray and read His word, the stronger we tend to become. The more we offer praises to Him, the more victories come our way. God will strengthen our heart and will clothe us with confidence so that we can go through any ordeal fearlessly. We get strengthened in our mind and our spirit. We will realize that we are becoming stronger and courageous because of God.
God’s word is always true. We should do our work of placing our trust in Him and waiting on Him, doing what He pleases, taking instructions from His word, etc., while He will do His job of strengthening and empowering us so that we will walk and not faint and run and shall not grow weary.