Just a line I came across this morning, and really liked:
The Talmud (Pesachim 112a) invokes a classic imperative:
הוי עז כנמר
Be bold like a leopard.
On this Rashi comments:
התחזק במצוה יותר משיכולת בידך
Strengthen yourself in a mitzvah beyond your abilities.
I find this compelling, and thought-provoking.
For further reading, I believe this ties into Beitzah 25b and Jewish boldness and Tosafot there on the caper bush; the Torah as עז in Zevachim 115b; and Sefer Chasidim 12, among other things.