Hiranyakeshigrihyasutra 1.3.10.5

1.3.10.5

āharantyasmā ahate vāsasī \ te abhyukṣya \ somasya tanūrasi tanuvaṃ me pāhi \ svā mā tanūrāviśa śivā mā tanūrāviśa \ ityantarīyaṃ vāsaḥ paridhāyāpa upaspṛśya tathaivottarīyamapareṇāgniṃ prāṅmukha upaviśati \5\

They bring him a pair of (new) garments that have not yet been washed. He besprinkles them (with water) and puts on the under garment with (the formula), 'Thou art Soma's body; protect my body! Thou who art my own body, enter upon me; thou who art a blissful body, enter upon me.' Then he touches water, (puts on) the upper garment with the same (Mantra), and sits down to the west of the fire, facing the east.