My translation of chapter 19: Karma
Subhuti, what do you think? If there is someone who uses all seven treasures of the whole physical world as alms, because of good Karma, does he get a lot of Merit?
Of course, World Holiness, this person gets a lot of Merit.
Subhuti, if the Merit is something fixed and with limit (實), I will not say "He gets a lot of Merit" . It is only because Merit is not something absolute and with limit (無[實] = 虛/空), therefore I say a lot of Merit.
Paul's comment: This chapter raises two important issues:
1. The issue of Karma: In addition to tackling the main question of where one should place one's restless mind, the Diamond raised a lot of subjects for Buddhists to learn and do follow up studies and practices. The subject of Karma is one of them. It is operationally define here (i.e. how it is being used) in a simply way, then the Buddha moved on to the following issue that appeared many times in the Diamond Sutra.
2. The issue of Absolute vs Illusion (or Solid vs Emptiness, or Substance vs void, 實 vs 虛/空). The most important concept in Buddhism. The dilemma is when we start talking about the meaning of any concept, by definition, we are delimiting some absolute (no matter how transient that absolute will stay) out of reality (which is void, Empty or concept-less). In Buddhism this reality is all encompassing and pre-concept, pre-language, pre-the-existence of any sentient being with a perceiving capability (however that perceiving is being defined - usually man will define it as human-language). Therefore there comes the important saying in the Heart Sutra (心經): 色即是空， 空即是色。 （Absolute is Void and Void is Absolute).