After he had spoken, a Pharisee invited him to dine at his home. He entered and reclined at table to eat. The Pharisee was amazed to see that he did not observe the prescribed washing before the meal. The Lord said to him, "Oh you Pharisees! Although you cleanse the outside of the cup and the dish, inside you are filled with plunder and evil. You fools! Did not the maker of the outside also make the inside? But as to what is within, give alms, and behold, everything will be clean for you. (Lk 11:37-41)
Jesus denounces the Pharisees while having a meal with them. Often Luke does this way: controversies with or reprimands of Pharisees are regularly set by Luke within the context of Jesus' eating with Pharisees (see Luke 5:29-39; 7:36-50; 14:1-24). So Jesus has not rejected the Pharisees and his table fellowship only goes to show that he is in relationship with them. They are his friends too. But they are criticized for what they do.
Jesus was a guest in the house of a Pharisee. But he did not follow the traditions. He was not just following the traditions of religious practices. It was all about attitudes. The Pharisee saw Jesus as law giver. But Jesus looked at God as a creator. If one has an attitude of God as law-giver then they see only rules and regulations. If the attitude is that of a creator God then it is all inclusive: both inside and out side of everything.
Why did Jesus say ‘give alms’? Here is a plain allusion to the law of Moses, by which it was provided that certain portions of the increase of their land should be given to the Levite, the stranger, the fatherless, and the widow; and, when that was done, what was reserved for their own use was clean to them, and they could in faith pray for a blessing upon it, Deut. 26:12-15. Then we can with comfort enjoy the gifts of God's bounty ourselves when we send portions to them for whom nothing is prepared.
