For example...
There are other instances of 72 appearing in religious texts as well. Is there a reason for all this, or is it merely coincidence?
72 is a very useful number.
It's divisible by 1, 2, 3, 4, 6, 12, 24, 36 and 72. It's a pronic number (It can be a solution to the equation n(n+1), an idea that dates back to Aristotle). It's also 2^3 x 3^2
This becomes even more apparent if you consider that many religions have their basis in astronomy and astrology. In the Ancient Babylonian version (the one we still sort of use), there are 12 signs in the night sky interacting with 6 bodies moving independently (The Moon, Mars, Venus, Jupiter, Saturn and Mercury - the others aren't visible until we start inventing telescopes). 6 multiplied by 12 is 72. This is just one example - as it's a number with a large number of factors, many of which have a large number of factors themselves, it pops up quite a lot.
It's also worth noting that some of these numbers are not set in stone. Some versions of Luke list 70, rather than 72.
" After these things the Lord appointed other seventy also, and sent them two and two before his face into every city and place, whither he himself would come. " - Luke 10:1, KJV
https://www.biblegateway.com/passage/?search=Luke+10%3A1%E2%80%9320&version=KJV
" After this the Lord appointed seventy-two others and sent them on ahead of him, two by two, into every town and place where he himself was about to go. " - Luke 10:1, ESV
https://www.biblegateway.com/passage/?search=Luke+10%3A1%E2%80%9320&version=ESV