But the Helper, the Holy Spirit, whom the Father will send in My name,
He will teach you all things, and bring to your remembrance all that I said to you.
John 14:26 (NASB)
He gives strength to the weary and increases the power of the weak.
Even youths grow tired and weary, and young men stumble and fall;
but those who hope in the Lord will renew their strength.
They will soar on wings like eagles; they will run and not grow weary,
they will walk and not be faint.
Isaiah 40:29-31 (NIV)
In the same way the Spirit also helps our weakness; for we do not know how to pray as we should, but the Spirit Himself intercedes for us with groanings too deep for words; and He who searches the hearts knows what the mind of the Spirit is, because He intercedes for the saints according to the will of God.
Romans 8:26-27 (NASB)
But as for you, continue in what you have learned and have become convinced of, because you know those from whom you learned it, and how from infancy you have known the Holy Scriptures, which are able to make you wise for salvation through faith in Christ Jesus. All Scripture is God-breathed and is useful for teaching, rebuking, correcting and training in righteousness, so that the servant of God may be thoroughly equipped for every good work.
2 Timothy 3:14-17 (NIV)