be not for sb to say

/biː nˌɒt fɔː ˌɛsbˈiː tə sˈeɪ/

/biː nˌɑːt fɔːɹ ˌɛsbˈiː tə sˈeɪ/

to be not for sb to say

to believe that it is not someone's place to make a decision or judgment on a particular matter and that it should be left to others who are more qualified or have more authority to do so