Is there a religious significance to the number nine?

I noted that we observed nine days of mourning for John Paul II. As a cradle Catholic, I remember that the number nine shows up in other areas of devotion or tradition, such as nine First Fridays in a row for plenary indulgences. I think there is a significance to the number nine but am unsure. Could you explain that for me?

While I cannot say for sure, my educated guess is that nine was chosen as a religiously significant number because it is the result of three times three. The number three is considered a number of perfection because of its association with the Trinity.

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