Isaiah 40:28-30

Knowest thou not? or hast thou not heard, that the euerlasting God, the Lord hath created the endes of the earth? he neither fainteth, nor is wearie: there is no searching of his vnderstanding.

But he giueth strength vnto him that fainteth, and vnto him that hath no strength, he encreaseth power.

Euen the yong men shall faint, and be wearie, and the yong men shall stumble and fall.