be in/take orders
be in holy orders
To have been ordained a priest. Holy Orders is the sacrament by which one becomes a priest. Michael always wanted to be a priest, so I'm not surprised to hear that he's in holy orders now.
take holy orders
To join the priesthood. Holy Orders is the sacrament by which one becomes a priest. Michael has always wanted to be a priest, and he's finally going to take holy orders later this year.
Farlex Dictionary of Idioms. © 2015 Farlex, Inc, all rights reserved.
be in/take (holy) ˈordersbe/become a priest: He wanted to take holy orders, but his father had other plans for him.
Farlex Partner Idioms Dictionary © Farlex 2017