Four Immeasurables, Compassion Part 2

The second line, the one about immeasurable compassion, snying rje, starts with this sentence.

sdug bsngal is suffering, another very common term when reading Buddhist texts. The rest part, dang sdug bsngal gyi rgyu, looks familiar from before. So this is suffering and the causes of suffering.

Also notice that the sentence implies that we are dealing with sems can thams cad.

All together, the second immeasurable has to do with all sentient beings, and their sufferings including the causes for their sufferings.