אבן עזרא — ועשו להם ציצת / וזכרתם את כל מצות ה'

Q — When should one wear tzitzit? Customary practice is to wear the tallit primarily during davening — but is this actually what the mitzvah is FOR?

A — Ibn Ezra reverses the customary emphasis. The function of tzitzit is to be "אות וסימן" preventing one from sin — "וזכרתם את כל מצות ה' ועשיתם אותם ולא תתורו אחרי לבבכם ואחרי עיניכם." When is the risk of sin? Not during tefilla — during tefilla one isn't sinning. Risk is in the marketplace, in daily commerce, walking among people. So Ibn Ezra reads the mitzvah as obligating a person to be wrapped in a four-cornered garment ALL DAY — "ולא יסירנו מעליו." The customary minhag of wearing tallit specifically at tefilla arose because Krias Shema mentions tzitzit, but Ibn Ezra says this misses the point: "יותר הוא חייב להתעטף בציצית בשאר השעות משעת התפלה." R' Avraham ben HaRambam in HaMaspik le'Ovdei Hashem explicitly endorsed this — calling tzitzit during commerce "ראויה ורצויה ביתר הדגשה." Both Rambam and his son did, however, still emphasize the importance of wearing tzitzit during tefilla — a halacha not in tension with Ibn Ezra's pshat but at a different level.