PFOA: "For Thine is the kingdom, the power and the glory forever."
This doxology is not found in the earliest manuscripts and so the recent translations have left it out. But it must have been in use in the Early Church whenever the Lord's Prayer was said and was found in the sources used by the translators of the King James Version.
It is fitting that the prayer ends with a doxology, with worship and praise. So that we do not fall into the trap of this being just a formula to be attached when we pray, let's think of its significance. We are ascribing to God the kingdom, the power and the glory.
Kingdom - Earlier, we prayed "Thy kingdom come". God's kingdom is here, and not yet. It's like us waiting for a loved one to arrive at the airport. The information display says "Landed". The plane has arrived, it is here. But we still waiting for her to pass through immigration and customs. She is here, but not yet. You are devoted to her, but has yet to see her, to be united with her, and receive what she has brought for you. In a similar way, God is King and rules in our lives today, but the full extent of His sovereignty is not acknowledged until Jesus returns and establishes His rule on earth. In the present age, sinful and rebellious humanity will deny and reject His authority, His Kingship.
Power - God is omnipotent and we ascribe to Him all power, hence we can claim "I can do all things through him who strengthens me". Yet we limit His power in two ways. Firstly, we think that God works only through the agency of man, through us. We do not allow for the "impossible". So we look for answers in science, economics, sociology or politics to solve the problems of the world, of society and even our in our own situations. Secondly we limit His powers when we turn to Him only when we are at a loss as to what to do next. Only after we've applied our knowledge in management, technology and psychology and find the problem intractable do we then turn to God. Sayings like "God help those who help themselves" and "If all else fails, try praying" have little support from the Bible.
Glory - We say and sing "to God be the Glory", and indeed He deserves all the glory. "The chief end (purpose) of man is to glorify God ...". But do we really? The cult of the celebrity did not begin with the paparazzi. Paul addressed it in 1 Cor. 1:12. Today, we need look no further than some of the advertisements for Christian concerts, conferences and meetings to realise that we often glorify man instead. In the first century, would we have gone to listen to Peter and John? After all, they were ignorant and unlearned (Acts 4:13). The result of their ministry was that "all men glorified God for that which was done" (Acts 4:21) and in the subsequent verses we read of the prayer of praise (verses 24-30).
God will not give His kingdom to another - He will not accept anyone or anything taking His place.
The power is God's alone - He enables us only to do His will, accomplishing it in His way.
Soli Deo gloria, Glory to God alone - Let your Father, who sees what is done in secret, reward you" (Matt. 6:18).