Here are the conventional English proverbs as I see applied to the field of software testing:
1. A journey of a 1000 miles begins with a single step.
A test run of a 1000 test cases begins with a sanity test.
2. Genius is 10% inspiration and 90% perspiration.
Software testing is 10% test preparation and 90% test execution.
3. As you make your bed, so you must lie in it.
As you write your test cases (good or poor; complete or incomplete), so you must execute them.
4. A bird in hand is worth two in the bush.
A confirmed bug is worth two suspects.
5. A chain is no stronger than its weakest link.
The quality of an application is no better than that of its most buggy component.
6. Discretion is the better part of valor.
Review is the better part of executing a task.
7. Empty vessels make the loudest noise.
People who least understand software testing speak of it in the most black-and-white terms.
8. An ounce of prevention is worth a pound of cure.
One bug fixed in the beginning is worth 16 updates.
9. A penny saved is a penny gained.
One test case re-used is a test case written.
10. Where there's a will, there's a way.
Where there's an application, there are bugs yet to be found.
Hope you enjoyed these :). If you like any other English saying, let me know. I will translate it to software testing.