Regarding Kṛṣṇa's heroism in fighting, there is the following statement: "My dear killer of the enemy, just as the elephant while taking bath in the lake destroys all the lotus stems within the water by swinging its trunk, so simply by moving Your arms, which are compared to the trunks of elephants, You have killed so many lotus-like enemies."
Regarding Kṛṣṇa's expertise in releasing weapons, when Jarāsandha, along with thirteen divisions of soldiers, attacked Kṛṣṇa's army, they were unable to hurt even one soldier on the side of Kṛṣṇa. This was due to Kṛṣṇa's expert military training. This is unique in the history of military art.
A person who is unable to bear another's distress is called compassionate.
Kṛṣṇa's compassion for distressed persons was exhibited when He released all of the kings imprisoned by Magadhendra. While dying, Grandfather Bhīṣma prayed to Kṛṣṇa and described Him as the sun which eradicated darkness. The kings who were imprisoned by Magadhendra were put into dark cells, and when Kṛṣṇa appeared there, the darkness immediately disappeared, just as if the sun had risen. In other words, although Magadhendra was able to imprison so many kings, upon the appearance of Kṛṣṇa they were all released. Kṛṣṇa did this out of His sincere compassion for the kings.