Isaiah 40:29-31

Leeser(i) 29 He giveth to the faint strength; and to the powerless he imparteth much might. 30 Though youths should grow faint and be weary, and young men should utterly stumble: 31 Yet they that wait upon the Lord shall acquire new strength, they shall mount up with wings as eagles; they shall run and not be weary, they shall walk, and not become faint.