"Then the word of the Lord came unto me, saying, Before I formed thee in the belly I knew thee; and before thou camest forth out of the womb I sanctified thee, and I ordained thee a prophet unto the nations. Thou therefore gird up thy loins, and arise, and speak unto them all that I command thee: be not dismayed at their faces, lest I confound thee before them." (Jeremiah 1:4-5, 17) What do you have to do? Is it something that requires a backbone of steel and nerves of the same? Did you know that for whatever it is you're called to do (it's probably that thing on the periphery--right there--you wouldn't dream of stepping into in a million years for fear of failing, yes), there's probably someone out there in this world--many people, I'd wager--who could do that very thing with their eyes shut and hands bound (who cares)? But you've been awakened, given sight and also freed by God to do this. As was Jeremiah. He was called to do a highly specific thing for the Lord. And God equipped him to do it, I should add. Earlier on in the chapter, God, as Jeremiah says, "put forth His hand, and touched my mouth. And the Lord said unto me, Behold, I have put my words in thy mouth." Um, before we go any further, do we need God to do that for us? Such a bold symbolism as God stretching forthe His right arm and taking His words--the very ones He wanted Jeremiah to speak--no more, no less (?)--and depositing them in the mouth of His prophet? Amazing. Because God would use them to "root out, and to pull down, and to destroy, and to throw down, to build, and to plant." (1:10) Huge things, no? Looking again at what we're tasked with, giving a word from the Lord to a co-worker, encouraging our spouse. Breaching a wall of silence or misperception. The point I'm getting at is this: what you're tasked with is no less important than the earthshaking things as was he.
"Then said I, Ah, Lord God! Behold, I cannot speak: for I am a child. But the Lord said unto me, Say not, I am a child: for thou shalt go to all that I shall send thee, and whatsoever I command thee thou shalt speak. Be not afraid of their faces: for I am with thee to deliver thee, saith the Lord." (1:6-8)
How did God do what He did to Jeremiah? Follow me a little in my facetious pedantry. Did He carve out each letter (from what kind of material?) and glue them together making "words" and then stuff them in Jeremiah's mouth? Did He serve him some sort of heavenly alphabet soup that, while chewing, in turn made up the words necessary (surely delicious)? This is symbolism, sure. However, for the Lord to do so bold a thing as put His words in Jeremiah's mouth, and reveal Himself doing it, no less, must've meant Jeremiah needed it. And in a society where age and wisdom and experience are preeminent, it would make sense that God would do what He did and also that Jeremiah would see his youthfulness as a liability in working out what God wanted him to do. Think about standing before the privy council. Think about coming from wherever and whenever you just met with the God of the universe, having had visions and experiences as did Jeremiah, and yet coming back into "normalcy", feeling the weight of your inadequacy and awkwardness (in a word, "youth") in light of "their faces". God will push you to the fore of whatever it is you're afraid. He'll ask you to speak what He told you in darkness. In the privacy of your time in His heart. He wants you to do this thing. He's not daring you because you're afraid, no. You're afraid, because you're supposed to do it. The fear came because the enemy saw what you were too young to see. But that's okay with God. You have His attention and His blessing. He's behind you to help you. He sees the end and you're not going to fail. Trust Him. The first chapter of Jeremiah ends thus:
"For, behold, I have made thee this day a defenced city, and an iron pillar, and brasen walls against the whole land, against the kings of Judah, against the princes thereof, against the priests thereof, and against the people of the land. And they shall fight against thee; but they shall not prevail against thee; for I am with thee, saith the Lord, to deliver thee." (1:18-19)
Do it.