What is the meaning of "in every being with a hot liver, there is a reward"?

The meaning of "in every moist liver is a reward" is that showing kindness to any living being by giving it water or similar acts is rewarded. The "moist liver" refers to a living being that still has life within it. This hadith has been narrated with different wordings, such as "ḥarāʾ" or "ḥarā," and no origin for the word "raṭibah" (moist) has been mentioned in dictionaries or commentaries on hadith.