AVŚ 19.27.3
तिस्रो दिवस् तिस्रः पृथिवीस् त्रीण्य् अन्तरिक्षाणि चतुरः समुद्रान् । त्रिवृतं स्तोमं त्रिवृत आप आहुस् तास् त्वा रक्षन्तु त्रिवृता त्रिवृद्भिः ॥३॥
tisro divas tisraḥ pṛthivīs trīṇy antarikṣāṇi caturaḥ samudrān | trivṛtaṃ stomaṃ trivṛta āpa āhus tās tvā rakṣantu trivṛtā trivṛdbhiḥ ||3||
Devanagari rendered by HREEM from the edition's roman (IAST) text; the IAST is the edition's own.
They call the heavens (dív) three, the earths three, the atmospheres three, the oceans four, the song of praise (stóma) triple, the waters triple: let these triple ones defend thee with the triple ones.
Translated by William Dwight Whitney (1905)