मनोमध्ये स्थितो मन्त्रो मन्त्रमध्ये स्थितं मनः ।
मनोमन्त्रं समायुक्तमेतद्धि जपलक्षणम् ॥
manaḥ-saṁharaṇaṁ śaucaṁ maunaṁ mantrārtha-cintanam |
avyagratvam anirvedo japa-sampatti-hetavaḥ ||
(Mantrārṇava; cited in Hari-bhakti-vilāsa: 17.129)
“Retraction of the mind [from objects of the senses], purity, silence, contemplation of the mantra’s meaning, non-agitation [i.e., steadiness], and non-dejection [i.e., perseverance, sustained enthusiasm] are causes of success in japa.”