Kol Ha'Olam Kulo gesher tzar maod v'haikar lo l'fached klal
כָּל הָעוֹלָם כֻּלוֹ גֶשֶׁר צַר מְּאֹד וְהָעִיקָר לֹא לְפַחֵד כְּלַל
[נוסח ר' נחמן מברסלב זקוצ"ל מספרו לקוטי מוהר"ן, תנינא מ"ח:
"ודע, שהאדם צריך לעבור על גשר צר מאד מאד, והכלל והעיקר שלא יתפחד כלל"]
The whole world is a very narrow bridge, but the important thing is not to fear at all
[Original context in the writings of Rabbi Nachman of Braslav:
"Understand: that when a person must cross a very, very narrow bridge, the most important and essential thing is that he not have any fear at all."]
While the first, briefer version of the song presented above is that which is popular, it is both a misquotation and a misrepresentation of its source, section 48 of the second part of the seminal oeuvre of Breslov chassidus, לקוטי מוהר"ן.
The distinction resides in the characterization of existential reality (in English: is the universe a bleak "very narrow bridge" OR is the metaphor reserved for a person's perception of his or her situational reality). A careful consideration of Breslov chassidus as presented by Rebbe Nachman and his student Reb Noson may reveal that the popular version of the song is in substantial conflict with its proported source.
The conditional tone of the passage ("that *when* a person must cross...") is evident from a simple reading of the entire passage:
כְּשֶׁיֵּשׁ חַס וְשָׁלוֹם, אֵיזֶה דּחַק וְעֵת צָרָה, חַס וְשָׁלוֹם וְדַע, שֶׁהָאָדָם צָרִיך לַעֲבר עַל גֶּשֶׁר צַר מְאד מְאד וְהַכְּלָל וְהָעִקָּר שֶׁלּא יִתְפַּחֵד כְּלָל
The textually faithful version is covered by Rav Yosef Karduner in his double album: Simanim Baderech-Road Marks & Kol Haolam (2000), track 11.
The tunes performed below by Otir and Jose Bucay were written by Baruch Chait. They are displayed here through license with ACUM, which represents Chait regarding this song.