Shiva Purana
समंत्रकं मां पतितः पूजयेद्यदि मोहितः ॥ नारकी स्यान्न सन्देहो मम पञ्चाक्षरं विना ॥ १० ॥
Yes, surely, if the fallen man, under delusion, were to worship me with other mantras, excluding the five-syllabled one, he is sure to fall into hell.
english translation
samaMtrakaM mAM patitaH pUjayedyadi mohitaH ॥ nArakI syAnna sandeho mama paJcAkSaraM vinA ॥ 10 ॥
hk transliteration by Sanscript