After a woman anoints Jesus with expensive perfume, the disciples rebuke her. But he responds (Mark 14)
7 For you always have the poor with you, and whenever you want, you can do good for them. But you will not always have me.
Sometimes the first phrase is used to justify accepting poverty and not taking action to alleviate it. For example, we should instead use our money to build expensive church buildings that will "glorify" God.
But, that is far from Jesus point. Here he is concerned with the (self-righteous) attitude and actions of his disciples at that very specific moment before his death. He is not giving a general principle for all of his followers for all time. Furthermore, he seems to be assuming that at other times his followers will be, can be, and should be helping the poor.
The second passage from Mark 12 concerns a poor widow contributing money to the temple.
41 And he sat down opposite the treasury and watched the people putting money into the offering box. Many rich people put in large sums. 42 And a poor widow came and put in twosmall copper coins, which make a penny. 43 And he called his disciples to him and said to them, “Truly, I say to you, this poor widow has put in more than all those who are contributing to the offering box. 44 For they all contributed out of their abundance, but she out of her poverty has put in everything she had, all she had to live on.”
This challenges my practical, functional, and pragmatic attitude towards giving money away (and raising it for worthy causes). To Jesus giving is an attitude and should be sacrificial and an act of worship.