Saṁhāram indicates that the Lord wanted to know the means by which those weapons that have been put into use can be withdrawn. He wanted to learn those mantras which cause the withdrawal of the weapons that been put to use through their respective mantras.

NOTE. Regarding weapons used in Vedic civilization, Śrīla Prabhupāda notes in his purport to Bhagavad-gītā 2.23: “It appears that there were many kinds of weapons made of earth, water, air, ether, etc., in addition to the modern weapons of fire. Even the nuclear weapons of the modern age are classified as fire weapons, but formerly there were other weapons made of all different types of material elements. Fire weapons were counteracted by water weapons, which are now unknown to modern science.”