• sasmāra — remembered
  Perfect of √smṛ. Balarāma does not call out, does not stretch out His hand — He simply remembers, and the weapons appear. Gauḍīyas note that smaraṇa is one of the nine limbs of bhakti (SB 7.5.23); here we see that the Lord's own smaraṇa is itself creative — what He remembers, manifests.
• mūṣalam — His club
  The musala (or mūṣala) is Balarāma's signature personal weapon alongside the hala. With the club He kills demons in close combat; the verse names the weapon by its specific function — para-sainya-vidāraṇam, that which tears asunder opposing armies.
• halam — His plow
  The hala marks Balarāma as the protector of agriculture and brāhmaṇical order. He alone among the Yādavas carries the plow as weapon — Gauḍīyas read it as the emblem of cultivation, of breaking the hard ground of the demonic heart open so that yajña can be re-planted there.
• daitya-damanam — which subdues the demons
  Compound: daitya (descendant of Diti, demon) + damana (subduer). The plow's adjectival epithet — the same instrument that prepares the earth for grain is the one that disciplines the daityas. Cultivation and chastisement are one act in the hand of Bhagavān.
• upatasthatuḥ — presented themselves
  Dual perfect of upa + √sthā, 'stood near.' The verb is reverential — the weapons do not arrive like tools; they stand attendant like servants. In Vaiṣṇava grammar the Lord's paraphernalia is conscious, and serves Him as His own retinue.

• What spiritual 'instruments' come to me at the thought, because I have built that readiness?
• Where is my training thin enough that the tool would not arrive in time?

Balarāma's hala and musala do not need to be fetched from an armory — He only remembers them and they stand at His side. The plow that breaks earth open and the club that breaks demons open are extensions of His will, the way Kṛṣṇa's flute is an extension of His breath. The weapons of Bhagavān are not instruments He picks up; they are limbs of His līlā that arrive the instant He turns His attention.