Shiva Purana
मंत्राणां जप एवं हि जपमादिक्रमाद्विदुः । सहस्रं ब्राह्मदं विद्याच्छतमैंद्र प्रदं विदुः ४४ ।
This is the tradition regarding the Japas. Repetition for a thousand times accords Brahmahood and that for a hundred times accords the region of Indra.
english translation
maMtrANAM japa evaM hi japamAdikramAdviduH । sahasraM brAhmadaM vidyAcchatamaiMdra pradaM viduH 44 ।
hk transliteration by Sanscript