Luke was a Greek physician who wanted to make sure he had the details correct in telling the story of Jesus. Luke approached his story much like a reporter would approach a news story. He interviewed people to ensure his facts were correct and detailed.
In Luke 1 we find Zechariah talking with Gabriel about his new son. Of course Zechariah did not believe the he was going to have a son and doubted the message that God had provided him through Gabriel. Looking back at many of the answered prayers that God has provided to me I catch myself looking at the answer right in front of me and saying, “You’ve got to be kidding….there is no way”. But God can do the impossible. Don’t be like Zechariah and me sometimes because, “For nothing is impossible with God” (Luke 1:37).