“He gave them new names”
The chief official gave them new names: To Daniel he gave the name Belteshazzar; to Hananiah, Shadrach; to Mishael, Meshach; and to Azariah, Abednego. (Daniel 1:7 BSB)
What it sounds like today
A routine administrative detail about assigning nicknames.
The cultural key
The renaming is a deliberate act of cultural conquest. Each youth's Hebrew name is a small creed built around the God of Israel: Daniel means 'God is my judge,' Hananiah 'the LORD is gracious,' Mishael 'who is what God is,' Azariah 'the LORD has helped', all carrying el ('God') or yah (the LORD). Their Babylonian replacements erase that and swap in Babylon's gods: Belteshazzar invokes Bel (Marduk), Abednego is 'servant of Nebo (Nabu),' and Shadrach and Meshach likely honor the moon-god Aku. So stripping the exiles of their God-bearing names and assigning them idol-bearing ones is an attempt to reprogram their very identity, to make them Babylonians who belong to Babylon's gods. That is the pressure the book's heroes quietly resist. A modern reader sees a clerk handing out nicknames; the first hearers saw an empire trying to overwrite whose these young men were.
Recovered meaning
The heroes' Hebrew names all confess the God of Israel; Babylon replaces them with names honoring its own gods (Bel, Nebo, Aku). The renaming is an attempt to re-own and reprogram the exiles' identity, not a trivial administrative note.