Should the phrase “rest in peace” be capitalized? Much depends upon the context, as well as the chosen written style of whatever piece of text the phrase appears in.
Is “Rest in Peace” Capitalized?
The phrase is commonly abbreviated to RIP (or R.I.P.) and is largely used in funeral services and on headstones. In this last usage, it would most commonly be capitalized for added emphasis, although sometimes the whole phrase is capitalized (REST IN PEACE).
Rest in Peace dates back to Christian burial traditions prior to the 5th century when the Latin phrase requiescat in pace began to appear as an epitaph for the souls of the deceased. It was not originally meant to suggest that the speaker wished the physical body of the deceased to remain undisturbed. Rather, it denoted a hope for the restful condition of the dead person’s soul in the afterlife.
It is now commonly used in a secular context as a statement spoken to honor the dead, without entailing any literal meaning. Sometimes in abbreviated form (RIP) it is used to express ironic dismay for the passing of a cultural artifact or fashion trend. Very recently the hashtag #RIP has been used on Twitter and other social media when a person of significance or fame passes away.
There is no strict grammatical reason to capitalize “rest in peace” since it is not a proper noun or noun phrase. However, doing so may help to highlight that the words are being used knowingly as a phrase with historical meaning and import. For instance, you might write: “we were choosing epitaphs and everyone agreed that the traditional Rest in Peace was best”. This would help make the phrase stand out, although putting quotation marks around a non-capitalized version or printing it in italics would also have the same effect.
If abbreviated as RIP, this must be capitalized, to prevent confusion with the word “rip” (a tear in something, or the act of tearing something).
A search of usages of this phrase in literature reveals that it is seldom capitalized, but that a few examples can be found. In summary, while there is no hard and fast rule that states that you must do so, if you intend to emphasize this stock phrase, then capitalization is as good a method as any.
In other words, Rest in Peace is just as correct as “rest in peace” or rest in peace.