It was kind of hard to see where it was going with the Doctor being artificially aged (even if it has happened twice before), and I originally wasn't keen on the Utopia humans being the protagonists. What can I say though, the script had me won over.
Martha was Earth's only hope, the Doctor gave her a secret message and she was sent on her way, to use this knowledge to save humanity. What did she do with this knowledge? We are led to believe that there is one weapon on the Earth that is capable of ending the Master's life... but it is separated into four parts (I rumbled this as a ruse as soon as I saw it). She has been seemingly walking the Earth seeking out the components of this weapon.
However this was not her genuine purpose at all. The mission the Doctor really charged her with, was to spread the word of who he was, what he had done and what he could do. Martha had only one weapon -words.... words and "prayer". All she really had was evangelism. She couldn't threaten the Master, she could only help other people to understand there was something better.
This is what it is like for genuine Christians. We don't have M4 or SA80 assault rifles, we don't have squadrons of joint strike fighters or fleets of warships... and we certainly don't have nuclear weapons. No, our equipment consists of:
"Therefore put on the full armor of God, so that when the day of evil comes, you may be able to stand your ground, and after you have done everything, to stand. Stand firm then, with the belt of truth buckled around your waist, with the breastplate of righteousness in place, and with your feet fitted with the readiness that comes from the gospel of peace. In addition to all this, take up the shield of faith, with which you can extinguish all the flaming arrows of the evil one. Take the helmet of salvation and the sword of the Spirit, which is the word of God. And pray in the Spirit on all occasions with all kinds of prayers and requests. With this in mind, be alert and always keep on praying for all the saints."
As the people begin their "prayer", The Doctor is surrounded by incandescent blue/white light and is restored to his former glory. He levitates over to the Master... and what is the first thing he offers him?
Forgiveness.
"You see, at just the right time, when we were still powerless, Christ died for the ungodly. Very rarely will anyone die for a righteous man, though for a good man someone might possibly dare to die. But God demonstrates his own love for us in this: While we were still sinners, Christ died for us. Since we have now been justified by his blood, how much more shall we be saved from God's wrath through him! For if, when we were God's enemies, we were reconciled to him through the death of his Son, how much more, having been reconciled, shall we be saved through his life! Not only is this so, but we also rejoice in God through our Lord Jesus Christ, through whom we have now received reconciliation."
"Rid yourselves of all the offenses you have committed, and get a new heart and a new spirit. Why will you die, O house of Israel? For I take no pleasure in the death of anyone, declares the Sovereign LORD. Repent and live!"
If that is you then please follow this link to a Keith Green song, close your eyes and pray the lyrics through.
Don't put it off... because you don't have any more regenerations.