Kautilya's Arthashastra 2.24.30

2.24.30

praśīrṇaṃ ca puṣpaphalaṃ devakāryārthaṃ vrīhiyavam āgrayaṇārthaṃ śrotriyās tapasvinaś cāhareyuḥ, rāśimūlam uñchavṛttayaḥ //

Those that are learned in the Vedas and those that are engaged in making penance may take from the fields ripe flowers and fruits for the purpose of worshipping their gods, and rice and barley for the purpose of performing ágrayana, a sacrificial performance at the commencement of harvest season, also those who live by gleaning grains in fields may gather grains where grains had been accumulated and removed from.