St. Teresa of Avila calls the Lord's Prayer the perfect prayer. She says "in its few words are enshrined all contemplation and perfection, so that if we study it no other book is necessary."
In Matthew, the disciples asked Jesus to teach them how to pray. Therefore, Jesus did that, he didn't just give them words to say nor did he tell them to recite this prayer as we usually do.
In Matthew 6, just preceding the Lord's Prayer, Jesus says "go to your inner room, close the door and pray to your Father in secret. And your Father who sees in secret will repay you."
He also says: "In praying, do not babble like the pagans, who think that they will be heard because of their many words." Jesus is instructing us to pray silently in an inward fashion.
Therefore, when we pray the Lord's Prayer, we do not need to rush through it, simply reciting words nor do we need to dwell intellectually on the meaning of the words.
We need to pray it from a listening heart. We need to let God speak to us through any one of the phrases. Each carries for us a special message from God.
Why does Jesus put this request into this prayer? Is he challenging the Father? Did Jesus challenge the Father in the agony in the garden when he asked that the forthcoming suffering be removed? I don't think so. Both are petitions to God along with "thy will be done."
"Lead us not into temptation" combines with "deliver us from evil," one phrased in the positive and the other in the negative. God does not lead us into temptation. Some versions say "subject us not." The very fact that we are creatures automatically subjects us to temptation.
What could this test or temptation be? I think it is the fundamental trial of humanity, that of our first parents: to want to be like God, to want to be God. It is the temptation with us always: an unwillingness to accept our human condition in its createdness, in all its weaknesses, in its need of God and others.
It is a refusal to live our full humanity in the way Jesus lived his, with its consequences of pain and suffering. It is rejection of true freedom and faithfulness to God's reign within us, free from illusions, from deceptions, from hypocrisy.
We are like the prodigal son of the Gospels who wants it all. We are constantly tempted to think that being rich and independent individuals who can take care of ourselves is the ultimate success. We don't want to have to rely on others and we don't want to help others.
It is, therefore, the temptation not to be a part of sinful humanity, even though that is exactly what we are. So, it is necessary to ask God to keep us grounded in our humanity and that is precisely what this petition does.
It's no wonder that St. Teresa says the Lord's Prayer "is a method of prayer which establishes habits that prevent the soul from going astray." She asks her sisters to try "saying the Pater Noster in this recollected way" for six months assuring them that they will have the great comfort of finding God within.
She adds that God taught her this method and she has "always gained such great benefit from this custom of interior recollection." Let's try it too.
I have never received a satisfactory interpretation of "lead us not into temptation" in the Our Father. Jesus prays, "Thy will be done" and in the next breath asks for something not to be done. If the Father wants to "put us to the test," why would Jesus ask that it not be so?