سَيِّدُ الْقَوْمِ فِي السَّفَرِ خَادِمُهُمْ
The leader of a group on a journey is the one who serves them.
Source: Bayhaqi.
سَيِّدُ الْقَوْمِ means the group's leader; فِي السَّفَرِ means “during travel,” and خَادِمُهُمْ means “the one who serves them.” Service is linked to honor and leadership.
سَيِّدُ الْقَوْمِ is an iḍāfah phrase. فِي is a preposition, السَّفَرِ is governed by it, and ـهُمْ in خَادِمُهُمْ refers to the companions. The nominal sentence identifies an important quality of leadership.
A travel leader does more than issue instructions: the needs, comfort, and safety of the companions are part of responsible leadership.