Who's Name was Jesus Baptized into??

[Esaias]

They did not use 'formulas' like we know and love today.

The biblical evidence indicates that when people went to be baptised by John, they confessed their sins. Thus, the ones being baptised 'spoke the words' that constituted the 'formula'.

However, from Biblical and ancient Judean practice, we can surmise (surmise only!) that when John baptised someone he spake a blessing of some kind, recognising their obedience and contritition towards God.

Interestingly enough, when Jesus was baptised we know for sure that Someone spoke, for the Voice came from heaven...