There are teachings about the dangers of riches that are common to Matthew, Mark and Luke. You cannot serve both God and Mammon, for example. So too the image of the camel trying to get through the eye of a needle is found in all three gospels: easier for him to do that than for a rich man to enter the kingdom of heaven.
But today's parable is found only in Luke's gospel. Along with his sensitivity and compassion, indeed because of it, Luke has a particular emphasis on the dangers of riches. He does not qualify the beatitude of the poor as Matthew does, adding the phrase 'in spirit' - happy are you poor is Luke's version, and it is he who adds the woes, beginning with 'woe to you who are rich'. Jesus does not say 'woe to you who are unduly attached to your possessions', or 'woe to you who are not sharing what you have with others'. Just having things is itself problematic.
'None of you can be my disciple unless he gives up all his possessions', we read in Luke 14. And Luke 16 is all about this warning against riches. There we find the crafty steward, the rich man and Lazarus, the Pharisees described as 'lovers of money', and a strange encouragement to the disciples to use money, 'that tainted thing', for the service of the kingdom.
In Luke we find Jesus's teaching about riches at its most radical. This teaching is here made physical, we might say. It is not a question of our attitude to our possessions, it is a problem that comes with having possessions at all. The warning is that human beings inevitably begin to find meaning and security and a sense of identity in their possessions. Rather than just using them, they become us somehow and we become them. We store up treasure of various kinds (not just money) to secure our lives, to give them meaning, and to establish ourselves in a sense of identity: to be someone. If it is by what we have that we become someone, then we have lost ourselves.
Jesus reminds us in today's gospel reading that 'one's life does not consist of possessions'. To act as if it does means to lose one's life. To be genuinely 'rich' means receiving the gift of the kingdom and practising the generosity which is at its heart: letting our possessions flow through us, we might say, not counting them as our own. It is another way of saying that we are to become like Jesus who, though he was rich, became poor, so that we who are poor might become rich.