Bhashya
स्वस्ति नः इत्यत्र स्वस्तिपदानां चतुर्णामपौनरुक्त्यं यास्कवचनात्°यथासंख्यम् ।स्वस्तीत्यविनाशमायुः नः अस्मभ्यम् इन्द्रः दधातु ; कीदृक् ? वृद्धश्रवाः वृद्धात् बृहस्पतेः सद्विद्याश्रवणं यस्य सः तथोक्तः दधातु ।स्वस्तीत्याभिमुख्यमुपासनायां नः अस्मभ्यम् पूषा विश्ववेदाः विश्वानि वेदांसि यस्य सः तथोक्तः, अथवा सर्वे वेदा उपासनायामाभिमुख्यं दधतु स्वस्ति नः अस्मभ्यं पूजार्हतां तार्क्ष्यः देवभक्तो गरुत्मान् अरिष्टनेमिः अहिंसितवज्रः दधातु ।स्वस्ति सुशोभनं नः अस्मभ्यं दधातु बृहस्पतिरित्यर्थः ।अस्मिन्मन्त्रे अस्मच्छब्दद्वि°प्सया वक्ष्यमाणायां विद्यायामादरं दर्शयति ।शान्तिः शान्तिः शान्तिः त्रिधा तु विघ्नोपशान्तिः वक्ष्यमाणविद्यानुष्ठाने ॥
In plain words
In 'svasti naḥ,' the word svasti is said four times without becoming redundant — Yāska himself tells us why: each time it belongs to its own deity in turn. Here it means an undecaying life; may Indra grant it. And what is Indra like? He is called 'of great fame' because he has heard true teaching from venerable Bṛhaspati — may that Indra grant it. Here svasti means a heart turned toward meditation; may Pūṣan, who holds all knowledge — or, in another reading, may all the Vedas themselves — turn us toward it. May Tārkṣya, Garuḍa devoted to the gods, whose thunderbolt is never touched, grant us the worthiness to worship. And here svasti means splendor itself; may Bṛhaspati grant it — that is the sense. Throughout this mantra, the word 'we' keeps returning, and that very repetition is a mark of reverence for the teaching about to unfold. As for 'peace, peace, peace' said three times over — that threefold peace is the quieting of every obstacle that could stand between us and the practice of what is about to be taught.
Close to the Sanskrit
Here, in 'svasti naḥ,' the non-redundancy of the four occurrences of the word 'svasti' [rests] on Yāska's statement, [taken] respectively. 'Svasti' [means] undecaying life; may Indra bestow [it] on us. Of what sort [is he]? 'Vṛddhaśravāḥ' — he by whom the hearing of true teaching from venerable Bṛhaspati [has been gained], so called — may he bestow it. 'Svasti' [means] readiness for meditation; may Pūṣan — he by whom all the Vedas [are known], so called, or alternatively, may all the Vedas — bestow readiness for meditation on us. May Tārkṣya — the god-devoted Garutmān, whose thunderbolt is unassailed, [called] ariṣṭanemi — bestow on us worthiness of worship. 'Svasti' [means] excellent glory; may Bṛhaspati bestow [it] on us — such is the meaning. In this mantra, by the wish for the twofold repetition of the word 'we', [the speaker] shows reverence toward the teaching about to be declared. 'Peace, peace, peace' is said threefold; this, however, [means] the removal of obstacles in the practice of the teaching about to be declared.