"If the cedars caught fire, what will the hyssops of the wall say?"

The other day, my mother used a Hebrew expression I hadn't heard before:

אִם בְּאֲרָזִים נָפְלָה שַׁלְהֶבֶת מָה יַגִּידוּ אֲזוֹבֵי הַקִּיר

It apparently comes from the Talmud, and its literal meaning is roughly "If the cedars caught fire, what will the hyssops of the wall say?", but obviously its real meaning is figurative. milog.co.il explains it thus:

When the strong and the precocious are hurt or fail, one can't expect the weak and the simple to have a better fate. [translation mine, improvements welcome]

I can't think of an English analogue for this. The closest I can think of is to combine two expressions and get something like:

If even Homer nods, what hope do the rest of us have?

Is there anything closer? (Or even an English version of the same expression?)

From the Hebrew Bible and prophet Jeremiah 12:5 - it may have the same sense: "If thou hast run with footmen, and they have wearied thee, how wilt thou then contend with horses? And if in a land of peace thou thinkest thyself in security, how wilt thou then do in the swelling of the Jordan?"