“If you fear” appears in the verse concerning shortening prayer during travel (al-Nisāʾ 4:101).
ʿUmar asked why travellers could shorten prayer when safety had returned. The Prophet ﷺ described the allowance as a gift or charity from Allah and instructed that it be accepted.
A circumstance mentioned in a verse need not always function as the only permanent legal condition when established prophetic explanation shows a wider application. The correct ruling emerges from reading the Qur'anic text with that explanation.