مُمِيتٌ بِلَا مَخَافَةٍ، بَاعِثٌ بِلَا مَشَقَّةٍ.
He causes death without fear and raises the dead (on the Day of Resurrection) without hardship.
Mumītun bilā makhāfah means that, when Allah causes someone to die, He has no fear of injury or retaliation from that person or the person’s relatives.
Fear can indicate inability, while Allah is absolutely powerful and free from inability.