Commentary for Berakhot 69:7

הא לא קשיא דאתיא בקל וחומר כשהוא שבע מברך כשהוא רעב לא כל שכן

This is no difficulty ; for we can use a fortiori reasoning — if he is to bless God when he is satisfied, how much more so when he is hungry ! We find this in connection with

Abraham Cohen Footnotes to the English Translation of Masechet Berakhot