HHDL had an excellent commentary on the cultivation of compassion.
He said that it depends on the 3rd deepest level of suffering. (I am not sure what the 1st two stages of suffering refer to). This stage of suffering is linked with a profound aspiration to achieve liberation and a fundamental vulnerability to suffering with mental afflictions (e.g., grasping).
My own take is that the practice of compassion is useless without the knowledge of this “root of suffering”. This is referred to as wisdom. Like the dorje with the bell, they must be practiced together with a sense of courage and strong feeling of concern.