And they slew a bullock
One of the three Hannah brought, unless the singular is put for the plural, and so all three were slain, some for sacrifice, and some for food perhaps; or if only one was slain, it might be offered as a sacrifice previous to the presentation of Samuel; or else was made a present of to Eli, at the introduction of Samuel to him, as follows:
and brought the child to Eli:
to be under his care, to he instructed and trained up by him in the service of the tabernacle; from hence it appears that Elkanah the husband of Hannah came along with her at this time.