Albert Barnes on Luke 2:37

And she was a widow of about four-score and four years. That is, she was about eighty-four years of age. It does not mean that she had been a widow for that long time.

Fastings and prayers (u) Constant religious service. Spending her time in prayer, and in all the ordinances of religion.

Night and day. Continually--that is, at the usual times of public worship and in private. When it is said that she departed not from the temple, it is meant that she was constant and regular in all the public services at the temple, or was never absent from those services. God blesses those who wait at his temple gates.

(u) Acts 26:7, 1Timm 5:5