The very commandment that promised life proved to be death to me.  For sin, seizing an opportunity through the commandment, deceived me and through it killed me. (ESV)
I have heard parents say to their children, "Child, you are going to be the death of me." It is usually the reckless behavior of children that would cause a parent to say that. The worry and concern that comes along with parenting can be intense. We want what is absolutely the best for our child and yet they often choose the very thing that would destroy them.
Paul is speaking of the Law and says, "You were going to be the death of me." Why is he saying this? Let's look at the idea that the commandment promised life. If it were possible for someone to fully keep the Law the promise would be holiness and life. What is the reality that Paul experienced? The Law was the death of him because it was impossible for him to keep it.
Sin enters the picture for Paul in relation to the Law. Sin deceived Paul into thinking that he could somehow be declared holy on his own efforts. This sinful deception continues today. Many of them are in our churches. Some of them are deacons. People who have been convinced that their own efforts can bring them holiness don't know that believing that lie will be the death of them.
When the Holy Spirit opens are eyes to the truth of God's Law it will always bring us to our own death. Death to self. Death to sin. Death to our trusting our own works. This is actually a good thing, because unless we are willing to die to sin we will never be reborn to new life in Christ. The Christian singer Steve Taylor once said, "If you don't die to yourself, pride kills."
Are you trusting in your own efforts? That will surely be the death of you. Instead of dying eternally, die to sin and accept the resurrection life that Jesus Christ provides.