The second half of the verse gives the life consequence of carrying about the -nekrosin- of Jesus. -y zoy tou Iysou en to somati ymon phanerothy- that the resurrection life of Jesus might be made visible in our body (repeated three times in 4:10-12). Obviously the verse is something to do with Lent. But it is not a cutting off of the flow of blood in our mortal body by asceticism, fasting, self denial, and all that we have imagined Lent should be.
So I read on quickly to the end of the Epistle to see if there are any clues to this principle of death and life. In the next chapter there is an explanation that, as a result of Jesus' death and resurrection, -myketi eautois zosin- Christians might no longer live looking to themselves (5:14), -alla to uper auton apothanonti kai egerthenti- but to the one who died and rose again. That is often taken to mean the self-denial of not living for our own benefit but for his. I prefer to think it means that we are to live with his death and resurrection in mind instead of minding our own weakness. That is how this section begins -echomen de ton thysauron touton en ostrakinois- we have this treasure (the knowledge of the glory of God in the face of Jesus Christ, (4:7) in fragile clay pots. And it is in our own fragility that -y uperboly tys dunameos y ek tou theou kai my ex ymon- the extraordinary power of God changes us, instead of our attempts to do this by our own efforts and will power..
At the end of the Epistle I found further clarification of Paul's model in terms of weakness and the power of God. Jesus -estaurothy ex astheneias- was crucified out of great weakness, -alla zy ek dunameos theou- but he lives (the verb that corresponds to zoy) -ek dunameos theou- out of the power of God (13:4) And then Paul goes on to say that we also are weak in the same way but -zysomen sun auto ek dunameos theou- we can live with him by drawing on the power of God (13:4).
This fits nicely with Paul's paradoxical statement "I have been crucified with Christ" - and (rather than the NRSV "nevertheless) as a result -zo de ouketi ego, zy de en emoi Christos- I live, but it's no longer I that lives, but Christ lives in me (Galatians 2:20). In Romans it turns out that the power of God (Romans 1:16) is not only the power Abraham lived by (Romans 4:16-24), but the power Paul himself lived by. He had discovered how he was totally unable to meet even his own standards (Romans 7:15-24). But the power of the Holy Spirit that raised Jesus from the dead (Romans 8:11) is available to anyone who will stop focussing on their own fleshly inability, and set their minds on what only the Spirit can do (Romans 8:5)
So what am I to do this Lent? Quit fussing about my own failures and limitations. Let them die by necrosis as I look to the Holy Spirit to do the needful in every situation I will face. That's all the good news I need.