"Before I formed you in the womb I knew you; before you were born I sanctified you; I ordained you a prophet to the nations."
Then said I: "Ah, Lord GOD! Behold, I cannot speak, for I am a youth."
But the LORD said to me: "Do not say, 'I am a youth,' for you shall go to all to whom I send you, and whatever I command you, you shall speak.
Do not be afraid of their faces, for I am with you to deliver you," says the LORD.
Then the LORD put forth His hand and touched my mouth, and the LORD said to me: "Behold, I have put My words in your mouth."
Jeremiah 1:4-9 (NKJV)