Have you ever noticed that lawyers like to say the same thing twice?
A marriage is to have and to hold; the partners who make and enter into it may covenant and agree that their goods and chattels are shared until they cease and desist, and the contract is declared null and void. On the death of one or either partner, the terms and conditions of the will and testament, witnessed truly and correctly, should be deemed and considered binding and obligating by the heirs and successors, and acknowledged legal and valid in the eyes of all and sundry.
This might give you a headache but there is a reason for all these word pairs, or legal doublets. And it is not because, like Dickens, the lawyers were paid by the word.
Doublets arose because after the Norman Conquest, French, Latin and Old English words were in currency, and their meanings overlapped. To be sure that both meanings were covered and avoid legal dispute, lawyers used pairs of words. While will and testament are Old English and Latin, and goods and chattels are English and French, have and hold are both English; doublets also began to be used for rhetorical effect.
An enjoyable little book called The Story of English in 100 Words by David Crystal can tell you more. Or listen to Stevie Wonder’s Signed, Sealed, Delivered for a quick introduction to legal triplets.
Translator, editor, writer, reader
found in translation 
I never, ever, undoubtedly realised this, that or the other.
Very interesting, nay, fascinating.