Paul was a man obsessed with doing right and pleasing God.  He aimed to be like Christ, something he seemed to work to achieve every day.  His confidence in death came as a result of succeeding in this endeavor.

2 Timothy 4:6-7 (KJV)
⁶  For I am now ready to be offered, and the time of my departure is at hand. ⁷  I have fought a good fight, I have finished my course, I have kept the faith:

Paul was confident about the life that he lived because, like a drink-offering, he had been poured out completely, and the stage he was in as he penned this epistle was his last.  In sacrifice, the drink-offering consisted of wine being poured out beside the altar just before the final blow that killed the animal was delivered.  Paul knew that was where he was in his life.  He had given himself completely to the Lord, and all that was left was for the final blow to be delivered.  Was he worried?  Did he have any regrets?  No.  He knew he had fought the fight, finished the course, and kept the faith.

What helped Paul live such a good life for the Lord was his total surrender.  That is the key for us as well.  If we want to be pleasing to God, and fight the good fight as Paul did, we must surrender ourselves to God completely.  This is how Paul described what he did.

 Galatians 2:20 (ESV)
²⁰  I have been crucified with Christ. It is no longer I who live, but Christ who lives in me. And the life I now live in the flesh I live by faith in the Son of God, who loved me and gave himself for me.

To be crucified with Christ is to put to death the old man that is selfish and self-serving, and put Christ and His cause first.  When Paul said that it was no longer him that was living, but Christ was living in him, he was saying that life consisted of doing the Lord’s will, not his own.  He often did things he did not necessarily want to do, or was not looking forward to doing, because he was controlled by a desire to do God’s will, not his own.  That is a part of what it means to be crucified with Christ.

Whose will was it for Christ to die on the cross in the way that He did?  We know it was not Jesus’ will because He said to the Father, “…my Father, if it be possible, let this cup pass from me; nevertheless, not as I will, but as you will” (Matthew 26:39).  Jesus did what He did not want to do because it was the will of God.  Paul did likewise.  The question is are we willing to do the same thing?

Who is in control of your life?  If Christ is living in us, we are allowing Him to be in control.  Notice, Jesus does not take control of us; that would be a loss of free will on our part, and God does not rob us of our free will.  We must give the controls of our life over to Jesus by crucifying the old man (our corrupt nature) and allowing Jesus to take his place.  This will determine how we live our lives and the results will be obvious.

The one who has been crucified with Christ, like Paul, will not live immorally.  Paul wrote, “And those who belong to Christ Jesus have crucified the flesh with its passions and desires” (Galatians 5:24).  Paul identified some of these passions and desires when he wrote to the brethren at Colossae.

Colossians 3:5 (ESV)
⁵  Put to death therefore what is earthly in you: sexual immorality, impurity, passion, evil desire, and covetousness, which is idolatry.

The one who is involved in sins such as these is living for himself, not Christ, and Christ is certainly not living in such a person.  If we want to maintain a relationship with Jesus, we must be sure that earthly things have been put to death.  These things consist of more than just immoral behavior.  Those crucified with Christ will avoid ungodly attitudes that lead to improper actions.  As Paul continued to write about this to the saints at Colossae, he said the following:

Colossians 3:7-9 (ESV)
⁷  In these you too once walked, when you were living in them. ⁸  But now you must put them all away: anger, wrath, malice, slander, and obscene talk from your mouth. ⁹  Do not lie to one another, seeing that you have put off the old self with its practices

Are you filled with wrath?  Do you slander others or speak obscenely?  Are you a liar, or do you harbor malice in your heart.  Any of these things would be signs that you have not crucified the flesh and Christ does not have the controls of your life.

Just like an uncrucified life is obvious, so is a life lived by one crucified with Christ.  In Galatians 2:20, Paul said that after he was crucified with Christ his life was now lived by faith in the Son of God.  This is how we know if we have really been crucified with Christ—we live by faith in the Son of God, trusting Him enough to let Him have the controls.