Daniel
Daniel 9:21ESV·traditional attribution

while I was speaking in prayer, the man Gabriel, whom I had seen in the vision at the first, came to me in swift flight at the time of the evening sacrifice.

John Calvin Reformed @genevareformer

In the last Lecture we explained the appearance of the angel to Daniel, who satisfied the eagerness of his desires. For he prayed with great earnestness when he perceived the time to have elapsed which God had fixed beforehand by the mouth of Jeremiah, while the people still remained in captivity.

Matthew Henry Presbyterian @wholebiblehenry

We have here the answer that was immediately sent to Daniel's prayer, and it is a very memorable one, as it contains the most illustrious prediction of Christ and gospel-grace that is extant in all the Old Testament. If John Baptist was the morning-star, this was the day-break to the Sun of righteousness, the day-spring from on high. Here is, I. The time when this answer was given. 1.

Commenting on Daniel 9:20-27

John Gill Reformed Baptist @doctorgill

Yea, whiles I was speaking in prayer,.... Which is repeated, that it might be observed, that while he was in prayer, before he had finished it, or got off of his knees, an answer was sent him; see Isa 65:24, even the man Gabriel, whom I had seen in the vision at the beginning; either at the beginning of Belshazzar's reign, in the third year...