Bhashya
भद्रं कल्याणम्, कर्णेभिरिति च्छान्दसम्, कर्णैः शृणु-याम शृणुम देवाः सन्तो वयम्. भद्रं कल्याणं पश्येमअक्षभिः चक्षुभिः यजत्राः यजनशीलाः; स्थिरैरङ्गैः हृद-याद्यैः सामाङ्गप्रणवसावित्रीयजुर्लक्ष्मीनृसिंहगायत्रीरूपैः मू-लमन्त्राङ्गव्याख्यानपरैः तनूभिः तनूमन्त्रैः 'यो वै नृसिंहोदेवो भगवान्यश्च ब्रह्मा तस्मै वै नमो नमः' इत्याद्यैः; तुष्टु-वांसः इति स्तुतिसाधनत्वेनोक्तत्वान् तनूशब्देन मन्त्रा गृह्य-न्ते, तथा अङ्गशब्देन च; तुष्टुवांसः स्तुवानाः स्तुतिं कुर्वाणाः.व्यशेम विगतरोगं विविधैहिकामुष्मिकसुखभोगक्षमम् अशेमप्राप्नुयाम; आयुरिति प्रत्येकं संबध्यते; यद्देवहितं देवःतापनीये उक्तविद्योपास्यः तत्तदवसरोचितकरणबुद्ध्याशिक्षन् हितमाचरति यस्मिन्नायुषि तत् तथोक्तमायुर्व्यशेमेतिसंबन्धः ॥
In plain words
Bhadram simply means the good. Karṇebhiḥ is an old Vedic form of karṇaiḥ, 'with the ears'; śṛṇuyāma means śṛṇuma, 'may we hear' — spoken by us, who here stand as the gods. Bhadram again means the good; paśyema means may we see; akṣabhiḥ means cakṣubhiḥ, with the eyes; and yajatrāḥ means those whose very nature is to offer sacrifice. Firm limbs means the organs beginning with the heart, taken as the Sāma, the Aṅga chants, the syllable Om, the Sāvitrī, a Yajus verse, the Lakṣmī mantra, the Narasiṃha mantra, and the Gāyatrī — all bent on unfolding the limbs of the one root mantra. With our bodies means with the body-mantras: those beginning, 'He who is truly Narasiṃha, the God, the Lord, who is also Brahmā — to him, salutation, salutation,' and the rest. Because tuṣṭuvāṃsaḥ has already been named as the means of praise, both the word 'body' and the word 'limb' are understood to mean these mantras. Tuṣṭuvāṃsaḥ itself just means those who are praising, who are singing praise. May we enjoy means: may we reach, may we attain, a life free of disease, fit for every pleasure this world and the next can hold. The word 'life' attaches to each of these in turn. And devahitam, 'allotted by the god,' means this: the deity taught for meditation in the Tāpanīya, teaching through whatever means each occasion calls for, brings about what is good — and the very life in which that happens is what is called, in this way, 'life.' That is how 'may we enjoy [this] life' is to be understood.
Close to the Sanskrit
'Bhadram' [means] kalyāṇam (the good). 'Karṇebhiḥ' is a Vedic (chāndasa) form [for] karṇaiḥ (with the ears); 'śṛṇuyāma' [means] śṛṇuma — 'we, being gods.' 'Bhadram' [again means] kalyāṇam; 'paśyema' [means] may we see; 'akṣabhiḥ' [means] cakṣubhiḥ (with the eyes); 'yajatrāḥ' [means] yajanaśīlāḥ (those whose nature is sacrifice). 'Sthirair aṅgaiḥ' [means] with [organs] beginning with the heart, in the forms of the Sāma, the Aṅga-mantras, the Praṇava, the Sāvitrī, the Yajus, the Lakṣmī, the Narasiṃha, and the Gāyatrī — intent on explaining the limbs of the root mantra. 'Tanūbhiḥ' [means] with the body-mantras, [mantras] beginning 'He who is indeed Narasiṃha, the god, the Lord, and who is also Brahmā — to him, salutation, salutation' and so on. Since 'tuṣṭuvāṃsaḥ' is stated as being the means of praise, by the word 'tanū' mantras are meant, and likewise by the word 'aṅga.' 'Tuṣṭuvāṃsaḥ' [means] stuvānāḥ, [i.e.] those performing praise. 'Vyaśema' [means]: may we obtain — may we attain — [a life] free of disease and capable of manifold pleasure and enjoyment here and hereafter. The word 'āyuḥ' is to be connected with each [clause] severally. As for 'yad devahitam': the deity, who is to be meditated upon per the teaching stated in the Tāpanīya [Upaniṣad], teaching by discernment of the means suited to each occasion, brings about what is beneficial; the life in which this occurs is called by that name; thus 'āyur vyaśema' is to be construed.