Kauṣītaki (Śāṅkhāyana) Brāhmaṇa 18.1.10

18.1.10

tad āsām devatānām āsīt /

marriage this thousand (of verses) that was in the possession of these deities; they said ‘Let us run a race for this thousand’; they ran the race; then the Açvins were victorious by means of the ass. Therefore are many gods celebrated, and yet it is called the Āçvina. Hence, moreover, the ass does not run with his full speed, considering himself worn out (because) ‘I have done my running.’ A thousand should he recite, for a thousand they too won.