وَفَى الْقَائِدُ بِوَعْدِهِ. الْوَفَاءُ مِنْ شِيَمِ الْكِرَامِ.
The leader kept his promise. Keeping promises is a trait of noble character.
A separate general maxim reinforces the particular action; in an appropriate context this is tadhyīl. Contrast:
رَجَعَ صَدِيقِي ـ وَاللَّهُ أَعْلَمُ ـ قَبْلَ الْمَغْرِبِ.
My friend returned—God knows best—before sunset.
The inserted comment adds a qualification or aside; it does not describe the friend's physical state during arrival. Its function is iʿtirāḍ, a parenthetical insertion. Both add words, but their syntactic places and rhetorical roles differ.