Our Rabbis have taught: Four things require strength : Torah, good deeds, prayer and the way of the world [i.e. proper behavior]. From where is it derived that Torah and good deeds [require effort] ? As it is said, "Only be strong and very courageous to observe to do according to all the law" (Josh. i. 7) — "be strong" in Torah, and "very courageous" in good deeds.
In the eyes of all Israel be strong and courageous. There are in this two meanings, as is the style of Deuteronomy. 1] That he said this in the eyes of the Israelites. 2] That he said to be strong in the eyes of the Israelites.
Another interpretation: “In the eyes of all Israel be strong and courageous”. Because the eyes of all Israel are on him, and they will learn from his example, so all the more so he needs to be strong in Torah and fear of Heaven in their eyes, following the principle “first adorn yourself [then adorn others]” (BT Baba Metzia 107b). He is like the peg that everything depends on him, and that is what is meant by “for you will bring this nation”...
The Hasidic master Rabbi Nachman of Breslov is known for his famous teaching: Kol haolam kulo gesher tzar me’od, vehaikar lo lefached klal. “The whole world is a very narrow bridge, and the main thing is not to fear at all.”
But Nachman’s actual recorded teaching is far subtler and closer to our experience. Rather than use the Hebrew word lefached (“to be afraid”), he uses the reflexive form, l’hitpached (“to cause oneself to be afraid”). For Nachman, courage is not about denying or repressing fear. Rather, the fundamental principle of courage is choosing not to frighten ourselves beyond the fear we already experience. Fear is unavoidable, perhaps even required. Courage involves moving forward despite our fear, and not exacerbating our anxieties.
(source: https://www.myjewishlearning.com/article/cultivating-jewish-courage-ometz-lev/)

"It's not fear that gets in the way of daring leadership; it’s armor. When things get tough, do we lean into vulnerability and get curious, or do we self-protect in ways that move us away from our values? Having to be the “knower” or always being right is heavy armor. It’s defensiveness, it’s posturing, and, worst of all, it’s a huge driver of [nonsense]."
Source: https://brenebrown.com/articles/2020/02/13/the-courage-to-not-know/