The better you know God, the easier it is to say yes when He calls.
Take Isaiah, for example:
Isaiah 6:1, 8 (NLT)
It was in the year King Uzziah died that I saw the Lord. He was sitting on a lofty throne, and the train of his robe filled the Temple …
Then I heard the Lord asking, “Whom should I send as a messenger to this people? Who will go for us?”
I said, “Here I am. Send me.”
Isaish knew God, up close and personal. He said, “Yes, Lord.”