Valmiki Ramayana Bala Kanda Sarga 27 Shloka 23

धीमतः of the sagacious, तस्य मुनेः ascetic Viswamitra, जपतः while muttering in a subdued tone, महार्हाणि venerable, अस्त्राणि astras, सर्वाणि all, राघवम् for Rama, उपतस्थुः (reached) served.

While the sagacious ascetic Viswamitra was muttering the mystic terms of these venerable astras (addressing their respective deities), all these weapons (with their mystic power) attended on Rama.