Yāska's Nirukta 13.4

13.4

``vi hi sotor asṛkṣata nendram devam amaṃsata/
yatrāmadad vṛsākapir aryaḥ pusteṣu matsakhā viśvasmād indra uttarah/''.
vyasṛkṣata hi prasavāya/
na ca indram devam amaṃsata/
yatra amādyad vṛsākapir arya īśvaraḥ pusteṣu posesu,.matsakhā mama sakhā madana sakhā/
ye naḥ sakhāyas taiḥ saha iti vā/
sarvasmād ya indra uttaras tam etad brūma ādityam/
atha eṣā aśvinoh/

"For they have left off pressing, nor did they revere Indra as a god,
where Vṛṣākapi, the lord, rejoiced in his nourishments, my friend; superior to all is Indra."
For they have ceased from pressing.
Nor did they revere Indra as a god,
where Vṛṣākapi rejoiced, the lord, the master, in nourishments, in fosterings; *matsakhā*: my friend, the gladdening friend;
or with those who are our friends.
He who is Indra, superior to all—him we declare to be Āditya.
Now this [verse] is of the Aśvins: