"Old Saying Values People's Word" by Susan Pearl

"Talking out of both sides of his (her) mouth".

"You're as good as your word".

"Don't make promises you can't keep".

We cannot tell everyone exactly what they want to hear.  If we go to one group and promise them we will say "Yes" on an issue--- And then we go to an opposing group and promise them we will say "No" on the issue then we are  "talking out of both sides of our mouth". "Yes" is coming out of one side of our mouth and then "No" is coming out of the other side.  It makes a double standard and before long people will not believe anything we say.  Because there is another old saying "You are only as good as your word".  We should keep our promises and live up to our word.  We should not make promises we cannot keep but say only the truth as we know it at that particular time.
Some situations are fluid and constantly changing and we have to go with the last current information to keep evaluating the truth that needs to be conveyed without bias or prejudice.