Nṛsiṁha pūrvatāpinī (first half) upaniṣad reveals “mantra rāja mantra”, the king of all mantras. Both gods and demons were scared of death and they approached Brahmā for a mantra to conquer death. Brahmā initiated them with mantra rāja mantra in anuṣṭupchandas (अनुष्टुप्छन्दः). Brahmā also told them that those who fear for death and sins should get mantra rāja mantra initiated. Following is mantra rāja mantra.

ॐ उग्रं वीरं महाविष्णुं ज्वलन्तं सर्वतोमुखम्।

नृसिंहं भीषणं भद्रं मृत्य्मृत्युं नमाम्यहम्॥

om ugraṁ vīraṁ mahāviṣṇuṁ jvalantaṁ sarvatomukham |

nṛsiṁhaṁ bhīṣaṇaṁ bhadraṁ mṛtymṛtyuṁ namāmyaham ||

The same upaniṣad reveals another powerful mantra known as “yajur mahālakṣmi gāyatrī mantra”. This mantra has twenty four akṣara-s like gāyatrī mantra. It is said that this mantra is capable of giving wealth and status. Following is yajur mahālakṣmi gāyatrī mantra.

ॐ भूर्लक्ष्मी भुवर्लक्ष्मीः सुवः कालकर्णी। तन्नो लक्ष्मीः प्रचोदयात्॥

om bhūrlakṣmī bhuvarlakṣmīḥ suvaḥ kālakarṇī | tanno lakṣmīḥ pracodayāt ||

A very powerful mantra can be formed by combining mantra rāja mantra and yajur mahālakṣmi gāyatrī mantra and this mantra is capable of conferring benefits of both the above mantras. If these two mantras are combined, we get the following mantra.

ॐ उग्रं वीरं महाविष्णुं ज्वलन्तं सर्वतोमुखम्।

नृसिंहं भीषणं भद्रं मृत्य्मृत्युं नमाम्यहम्॥

ॐ भूर्लक्ष्मी भुवर्लक्ष्मीः सुवः कालकर्णी। तन्नो लक्ष्मीः प्रचोदयात्॥

om ugraṁ vīraṁ mahāviṣṇuṁ jvalantaṁ sarvatomukham |

nṛsiṁhaṁ bhīṣaṇaṁ bhadraṁ mṛtymṛtyuṁ namāmyaham ||

om bhūrlakṣmī bhuvarlakṣmīḥ suvaḥ kālakarṇī | tanno lakṣmīḥ pracodayāt ||