The tower of strength British phrase
My roommate was a tower of strength to me when I was ill.
After losing my job, my boyfriend was a tower of strength and gave me encouragement to start looking for another job.
My dad is a tower of strength to my family.
A group of bad or sinful people
To count the number of people in a group to determine who is present
This idiom is used as a noun in the sentence.
This one is opposite to the idiom "in an ivory tower".
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This idiom derives from The Book of Common Prayer, 1549: "O lorde... Bee vnto them a tower of strength."
And also was later used in Richard III, 1594 by Shakespeare: "The king's name is a tower of strength."
A legal matter that is very easy to solve
The house owners didn't lock the doors before going out, and that's why they got broken in. This is an open and shut case.