You demonstrated the strength of your arm only after rallying a thousand hands; even if they turn out to be sufficient, they still have to face great tests.

In this couplet, the poet playfully yet sharply calls out someone boasting of their strength. You flex your muscle with great pride, but only after leaning on a thousand supporting hands to lift it. Even if all that borrowed help manages to see you through, the poet reminds us, the real and grueling test of true character is still waiting ahead.