جَاءَنِي الْقَوْمُ أَكْثَرُهُمْ
Most of the people came to me.
«The people» introduces a collective; «most of them» then selects a substantial portion as the intended partitive substitute. The predication is thus focused on most members, not necessarily every member.
Unlike whole-for-whole substitution, this construction does not make both phrases coextensive. The second expression selects part of what was first mentioned.