Then Saul said to David, "You are not able to go against this Philistine to fight with him, for you are but a youth and he has been a warrior from his youth." But David said to Saul, "Your servant was tending his father's sheep. When a lion or bear came and took a lamb from the flock, I went out after him and attacked him and rescued it from his mouth.... Your servant has killed both the lion and the bear; and this uncircumcised Philistine will be like one of them" from I Samuel 17
God prepares us for great deeds in our private acts of courage and faith in mundane daily tasks. My mom calls these "lion and bear stories."
The Lord "does not despise small beginnings."
"Peter, do you love me? Tend my sheep."