Jami At Tirmidhi
767
Sahih+2

Abu Qatadah said:"It was said: 'O Messenger of Allah! What is the case of the one who fasts daily?' He said: 'He did not fast nor break (the fast).'" Or, he said: "He never fasted nor broke (his fast)

SahihAhmad Muhammad Shakir
SahihAl-Albani