This is one of the dozen or more
ceremonial purification baths that
are just beside the main entrance to
Temple Mount (just a stone's throw
from where Peter preached in Acts
chap#2) There is little doubt that
this is exactly where the 3000 were
immersed in Christian Baptism in
response to Peter's sermon, in Acts
Chap#2... It would've been the most
practical and convenient place near
to the Portico of the Temple...