Symbolism, Imagery, Allegory
Also known as the "Our Father," the Lord's Prayer has become the quintessential Christian prayer, and it is still spoken each week in many churches across the U.S. In Luke, it reads like this:
"Father, hallowed be your name. Your kingdom come. Give us each day our daily bread. And forgive us our sins, for we ourselves forgive everyone indebted to us. And do not bring us to the time of trial." (11:2-4)
You might wondering where "our Father in heaven," "your will be done, on earth as it is in heaven," and "deliver us from evil" all went. Well, those are from Matthew 6:9-13, so don't look too hard.
Jesus recites this prayer to show the disciples the value of "short and sweet." In one passage, Jesus actually mocks a Pharisee's defunct prayer, in which he uses twenty-nine Greek words to thank God for making him better than everyone else (18:11-12). On the other end of the spectrum, he commends the six-word prayer of a tax collector who simply asks God to forgive him for being a sinner (8:13).
Bottom line: next time you pray, remember that it's quality over quantity.
Annoying God
If at first you don't succeed, try, try, try again.
Jesus may not have said as much, but it's definitely his Prayer Rule #1. Bug God till he gives you what you want.
Human examples? Jesus has plenty: it's like an annoying friend who knocks on his neighbor's door in the middle of the night until the neighbor gets up and gives his friend what he wants (11:5-8). Or a widow who pesters a judge so much that he grants her justice so that she'll stop nagging him (18:1-7). If these people—mere mortals—give the askers what they want, God will clearly do the same.
Luke's Jesus is pretty confident about all of this, actually:
"So I say to you, Ask, and it will be given you; search, and you will find; knock, and the door will be opened for you. For everyone who asks receives, and everyone who searches finds, and for everyone who knocks, the door will be opened." (11:9-10)
How's that for clear?