Shiva Purana
ओमित्येकाक्षरं ब्रह्म व्याहरन्मां त्वया सह ॥ चिंतयेन्मध्यतस्तस्य नित्यमुद्युक्तमानसः ॥ ६९ ॥
Repeating the single-syllabled Brahman Om, he shall with alert mind think of me along with you in the middle.
english translation
omityekAkSaraM brahma vyAharanmAM tvayA saha ॥ ciMtayenmadhyatastasya nityamudyuktamAnasaH ॥ 69 ॥
hk transliteration by Sanscript