Theravāda Vinayapiṭaka
Monks’ rules and their analysis
Monks’ Training (Sekhiya) 27
… in Anāthapiṇḍika’s monastery. Now at that time the group of six monks accepted almsfood inattentively, as though desirous of throwing it away … “…
‘Attentively will I accept almsfood,’ is a training to be observed.”
One should accept almsfood attentively. Whoever out of disrespect accepts almsfood inattentively, as though desirous of throwing it away, there is an offence of wrong-doing.
There is no offence if it is unintentional … if he is the first wrong-doer.