"Jesus said to him, 'If you wish to be complete, go and sell your possessions and give to the poor, and you will have treasure in heaven; and come, follow Me.'" (Matthew 19:21)
And Luke has something similar:
"Sell your possessions and give to charity; make yourselves money belts which do not wear out, an unfailing treasure in heaven, where no thief comes near nor moth destroys. For where your treasure is, there your heart will be also." (Luke 12:33-34)
While the verse in Matthew is directed toward the rich young ruler, the verse in Luke is directed toward all Jesus' disciples.
Jesus did not say to us to "sell all your possessions" but He said "sell your possessions", which means sell however much a person is willing to give to charity. Jesus said this so that we would have fewer attachments on earth and have much more worthwhile treasure in heaven.
Practically, this means we should help other people with our finances.
However, this does not mean that other people will have everything and we have nothing. But it is so that those in need will have something and there would be equality:
"For if the willingness is there, the gift is acceptable according to what one has, not according to what one does not have. Our desire is not that others might be relieved while you are hard pressed, but that there might be equality. At the present time your plenty will supply what they need, so that in turn their plenty will supply what you need. The goal is equality, as it is written: 'The one who gathered much did not have too much, and the one who gathered little did not have too little.'" (2 Corinthians 8:12-15)
Jesus honored those who gave more percentage-wise (e.g. the widow who gave 2 copper coins). See Mark 12:41-44. But the percentage or amount we give (that is more than 10%) is not a command but a free will offering.
10% of a person's income is the tithe. It was commanded by God for us to give (see Malachi 3:10).
Beyond that is free will offering to God.
God encourages giving more. But God loves a cheerful giver, who is not giving out of force:
"Each one must do just as he has purposed in his heart, not grudgingly or under compulsion, for God loves a cheerful giver." (2 Corinthians 9:7)
So each person should only give above 10% what he is willing to give (not forcing himself to do it).