Possible meanings are 1) she had been a widow for eighty-four years or 2) she was a widow and was now eighty-four years old.
## never left the temple ##
This is probably an exaggeration meaning that she spent so much time in the temple that it seemed as though she never left it. It could be translated as "was always at the temple" or it could state the meaning without the hyperbole: "was often at the temple." (See: [[rc://en/ta/man/translate/figs-hyperbole]])
## with fastings and prayers ##
"by abstaining from food and by praying"
## came up to them ##
"approached them" or "went to Mary and Joseph"
## the redemption of Jerusalem ##
This could be translated as "the one who would redeem Jerusalem" or "the person who would bring God's blessings and favor back to Jerusalem." Here the word "redemption" is used to refer to the the person who would do it. (See: [[rc://en/ta/man/translate/figs-metonymy]])