CC Madhya 11.114

tāhāṅ upavāsa, yāhāṅ nāhi mahā-prasāda
prabhu-ājñā-prasāda-tyāge haya aparādha
Synonyms: 
tāhāṅ — there; upavāsa — fasting; yāhāṅ — where; nāhi — there is not; mahā-prasāda — remnants of food of the Lord; prabhu-ājñā — direct order of Śrī Caitanya Mahāprabhu; prasāda — remnants of food; tyāge — giving up; haya — there is; aparādha — offense.
Translation: 
“When mahā-prasādam is not available, there must be fasting, but when the Supreme Personality of Godhead directly orders one to take prasādam, neglecting such an opportunity is offensive.