Narada Purana — Purva Bhaga, Shloka 14
Mantraśodhana, Dīkṣā-krama, Guru-Pādukā, Ajapā-Haṃsa, and Ṣaṭcakra-Kuṇḍalinī Sādhana
साध्यः सुसिद्धो द्विगुणात्साध्यारिर्हंति बांधवान् । सुसिद्धसिद्धोर्द्धतया तत्साध्यो द्विगुणाज्जपात् ॥ १४ ॥
sādhyaḥ susiddho dviguṇātsādhyārirhaṃti bāṃdhavān | susiddhasiddhorddhatayā tatsādhyo dviguṇājjapāt || 14 ||
“当成者（sādhya）”以加倍用功而成“善成（susiddha）”；sādhya之敌会加害其亲族。然而凭借“善成且成（susiddha-siddha）”之增上力，那同一sādhya又可由加倍持诵（japa）而再得成就。
Narada (teaching within the Vedanga/technical instruction context, traditionally framed as Narada’s discourse to the Sanatkumara tradition)
Vrata: none
Primary Rasa: shanta
Secondary Rasa: bhayanaka
FAQs
It teaches that mantra-attainment has graded stages (sādhya → susiddha → siddha) and that obstacles can arise, but disciplined increase in japa strengthens attainment and restores the practitioner’s progress.
Though technical, it supports bhakti-sādhana by emphasizing steady repetition (japa) as a devotional discipline that intensifies inner power and protects one’s spiritual life from disruptive forces.
It reflects applied ritual-science: quantifying japa (doubling the count/effort) and recognizing stages of mantra-siddhi—typical of the technical instruction style associated with Vedanga-adjacent practice.