I've heard this phrase a couple of times.
What is it?
It is your "Calling and election made sure"; "receiving the second comforter"; "The more sure word of prophecy".
Sometimes it is referred to as the second endowment. In the early days of the church, getting ones second endowment was quite common, and did not neccessarily carry with it the implications that it became known for later.
With the passage of time, the second endowment involved a couple receiving an invitation from a member of the twelve. From my understanding, part of the endowment took place in the temple, and the second portion, in the couples home. In the last portion they had the opportunity to "Seek the face of the lord", if they so wished, which was nothing less than a visitation from Christ himself.
That is what I recall from my days in middle earth, but I have to admit that it has been along time since I was in the shire....