The Apostle of Allah ﷺ forbade them (his Companions) to observe Saum Wisal out of mercy for them. They said: You (Holy Prophet) yourself observe it. Upon this he said: I am not like you. My Lord feeds me and provides me drink. (Using translation from Muslim 1105)   

نَهَى رَسُولُ اللهِ ﷺ عَنِ الْوِصَالِ رَحْمَةً قَالُوا يَا رَسُولَ اللهِ إِنَّكَ تُوَاصِلُ قَالَ «إِنِّي لَسْتُ كَأَحَدِكُمْ يُطْعِمُنِي رَبِّي وَيَسْقِينِي»