Matthew 19:21-24 - The Rich Young Man
21 Jesus said to him, ‘If you wish to be perfect, go, sell your possessions, and give the money to the poor, and you will have treasure in heaven; then come, follow me.’ 22 When the young man heard this word, he went away grieving, for he had many possessions.
23 Then Jesus said to his disciples, ‘Truly I tell you, it will be hard for a rich person to enter the kingdom of heaven. 24 Again I tell you, it is easier for a camel to go through the eye of a needle than for someone who is rich to enter the kingdom of God.’
Mark 10:21-24 - Tells the Story Again
21 Jesus, looking at him, loved him and said, ‘You lack one thing; go, sell what you own, and give the money to the poor, and you will have treasure in heaven; then come, follow me.’ 22 When he heard this, he was shocked and went away grieving, for he had many possessions.
23 Then Jesus looked around and said to his disciples, ‘How hard it will be for those who have wealth to enter the kingdom of God!’ 24 And the disciples were perplexed at these words. But Jesus said to them again, ‘Children, how hard it is to enter the kingdom of God! 25 It is easier for a camel to go through the eye of a needle than for someone who is rich to enter the kingdom of God.’
Luke 6:27-31 Love For Enemies
27 ‘But I say to you that listen, Love your enemies, do good to those who hate you, 28 bless those who curse you, pray for those who abuse you. 29 If anyone strikes you on the cheek, offer the other also; and from anyone who takes away your coat do not withhold even your shirt. 30 Give to everyone who begs from you; and if anyone takes away your goods, do not ask for them again. 31 Do to others as you would have them do to you.
I don't think the point is that money, or having money, is bad but rather that we need to consider the transitory nature of material things and how putting these things above all else interferes with spiritual growth - or if you aren't the sort who's interested in spiritual growth - how striving after transitory things is a guarantee for a life filled with unhappiness, worry and striving for ever more objects.
To put it in practical terms Jesus is telling us that, Joy, peace of mind, and true freedom do not come from accumulating wealth but rather by giving up all we have (worries, false Gods, addictions) and showing compassion for others. Very few are going to take that advice literally but at least we can remember the spirit even if we don't always live by the letter.
The real bottom line is that Christianity is a religion of love and compassion and those two key criteria should inform how Christians choose to lead their lives.