Vaishnava Dharmashastra 51.78

51.78

māṃ sa bhakṣayitāmutra yasya māṃsam ihādmy aham
etan māṃsasya māṃsatvaṃ pravadanti manīṣiṇaḥ //

(An eater of flesh must say within himself), Me he (mâm sa) will eat in the next world, whose flesh I am tasting here. This, say the learned, is the derivation of the word flesh (mâmsa).