when push comes to shove
US /wen pʊʃ kʌmz tə ʃʌv/
UK /wen pʊʃ kʌmz tə ʃʌv/

1.
when a situation becomes urgent or difficult; when it really matters
:
•
When push comes to shove, he's always there for his family.
•
We can talk about it now, but when push comes to shove, we'll see who's really committed.