The Amidah is the central prayer in Jewish worship. It was originally 18 blessings, recited 3 times a day by religious Jews. At some point one of the blessings was split in 2, so it's now 19 blessings. Before beginning this prayer, we stand facing Jerusalem, and prepare ourselves by
1. Taking 3 steps backwards "Lord, open my lips..."
2. Then taking 3 steps forwards "...and my mouth shall speak Your praise!"
Even praising G*d we cannot do unless He opens our lips for us. But we CAN ask Him to do so! We can ask G*d to give us the power to do that which we ought. If He can give us the power, and if furthermore we NEED him to give us the power before we can act, whence do we get the power to ask? It is the tension of free will vs. determinism right there! If we have the free will to ASK, why do we have to ask? Why cant we just DO? In this short sequence, we accept and embrace the tension, and use it to energize the prayer which follows.