MURMURING IS A DEADLY SIN

Isa 29:24-30:1

24 Those who err in spirit will come to understanding, and those who murmur [discontentedly] will accept instruction.

Chapter 30

1 WOE TO the rebellious children, says the Lord, who take counsel and carry out a plan, but not Mine, and who make a league and pour out a drink offering, but not of My Spirit, thus adding sin to sin;
AMP