Literature Reference: 夙夜在公，寔命不同。——《诗经·小雅·鹿鸣》 Diligent day and night in public service, truly fate is different. Source from 'The Book of Songs: Xiao Ya, Lu Ming'.
夙: Original meaning: morning; formerly, in the past.
Meaning: Su signifies early and diligent, symbolizing hard work and effort.