SB 6.16.28
tatah sa sapta-ratrante
vidyaya dharyamanaya
vidyadharadhipatyam ca
lebhe ’pratihatam nrpa
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
O King Pariksit, after only one week of repeatedly practicing the mantra received from the spiritual master, Citraketu achieved the rule of the planet of the Vidyadharas as an intermediate product of his spiritual advancement in knowledge.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
If a devotee, after being initiated, adheres rigidly to the instructions of the spiritual master, he is naturally endowed with the material opulences of vidyadhara-adhipatyam and similar posts as by-products. A devotee need not practice yoga, karma or jñana to achieve a successful result. Devotional service alone is competent to award a devotee all material power. A pure devotee, however, is never attached to material power, although he gets it very easily without personal endeavor. Citraketu received this side benefit of his devotional service, which he rigidly performed in accordance with the instructions of Narada.