If you can keep your head when all about you Are losing theirs and blaming it on you,

If you can trust yourself when all men doubt you,

But make allowance for their doubting too;

If you can wait and not be tired by waiting,

Or being lied about, don't deal in lies,

Or being hated, don't give way to hating,

And yet don't look too good, nor talk too wise

—“If,”
Rudyard Kipling

How does the repetition in the stanza support the idea of building a strong character?

by giving a list of strong character traits
by showing that waiting, being lied about, and being hated are admirable
by indicating that endurance and patience are traits of someone with a strong character