"All it takes for evil to prevail is for good people to do nothing."

Old Adages:

All it take for evil to prevail is for good people to do nothing.

A stitch in time saves nine.

He who hesitates is lost.

The pot is calling the kettle black.

Marry in haste/repent in leisure.  (Or elect)

Sleep with dogs - get up with flees.

"O, what a tangle web  we weave when first we practice to deceive."
Walter Scott - Scottish  poet and novelist  (1771 -1832)