serve the purpose
serve one’s purpose
To be useful, to suit one’s needs or requirements.
I don’t have a screwdriver to open this, but I think that a knife will serve the purpose.
Jane prefers working to studying, so it served her purpose to drop out of school and take that job.
set back on one's heels
knock back on one's heels
To give an unpleasant surprise; upset suddenly; stop or turn back (someone's) progress.
Jack brags too much and it set him back on his heels when the coach told him he wasn't as good a player as he thought he was.
Jean was doing very well in school until sickness knocked her back on her heels.
set in one's ways
Stubborn; opinionated; unchangeable.
My grandfather is so old and set in his ways that he'll eat nothing new.
set one's cap for
To attempt to win the love of or to marry. Usually used of a girl or woman.
The young girl set her cap for the new town doctor, who was a bachelor.
set one's face against
To be very much against; strongly disapprove.
The banker's daughter wanted to marry a poor boy, but her father set his face against it.
set one's heart on
have one's heart on
heart set
To want very much. To be very desirous of; hope very much to succeed in. Used with a verbal noun.
He set his heart on that bike.
He set his heart on winning the race.
She has her heart set on taking a trip abroad. She's been thinking about it for months.
Todd has his heart set on going to medical school and becoming a doctor.
set one's mind at rest
To relieve someone's anxieties; reassure someone.
"Let me set your mind at rest about the operation," Dr. Vanek said. "You'll be back on your feet in a week."
set one's mind on
To be determined to; decide to.
He has set his mind on buying an old chateau in France.