Moses said to God, “Who am I that I should go to Pharaoh and bring the children of Israel out of Egypt?” He said, “But I will be with you.”

Exodus 3:11-12 (ESV)

The Lord said to Jeremiah:

Do not say, “I am only a youth”; for to all to whom I send you, you shall go, and whatever I command you, you shall speak.

Jeremiah 1:7 (ESV)