Thrice was I beaten with rods - This was under the Roman government, as their lictors beat criminals in this way. We hear of the apostle's being treated thus once, namely at Philippi, Acts 16:22. See Section 9 of the Introduction.

Once was I stoned - Namely, at Lystra, Acts 14:19, etc.

A night and a day I have been in the deep - To what this refers we cannot tell; it is generally supposed that in some shipwreck not on record the apostle had saved himself on a plank, and was a whole day and night on the sea, tossed about at the mercy of the waves. Others think that βυθος, the deep, signifies a dungeon of a terrible nature at Cyzicum, in the Propontis, into which Paul was cast as he passed from Troas. But this is not likely.

I beaten.

Acts 16:22,23,33,37 And the multitude rose up together against them: and the magistrates rent off their clothes, and commanded to beat them...

Acts 22:24 The chief captain commanded him to be brought into the castle, and bade that he should be examined by scourging...

once.

Matthew 21:35 And the farmers took his servants, and beat one, and killed another, and stoned another.

Acts 7:58,59 And cast him out of the city, and stoned him: and the witnesses laid down their clothes at a young man's feet, whose name was Saul...

Acts 14:5,19 And when there was an assault made both of the Gentiles, and also of the Jews with their rulers, to use them spitefully...

Hebrews 11:37 They were stoned, they were sawn asunder, were tempted, were slain with the sword: they wandered about in sheepskins and goatskins...

thrice.

Acts 27:1-44 And when it was determined that we should sail into Italy, they delivered Paul and certain other prisoners to one named Julius...

What 'the Gospel' Is
The beginning of the gospel of Jesus Christ.--Mark i. 1 My purpose now is to point out some of the various connections in which the New Testament uses that familiar phrase, 'the gospel,' and briefly to gather some of the important thoughts which these suggest. Possibly the process may help to restore freshness to a word so well worn that it slips over our tongues almost unnoticed and excites little thought. The history of the word in the New Testament books is worth notice. It seldom occurs in those …
Alexander Maclaren—Expositions of Holy Scripture

But when He Might Use to Work, that Is...
15. But when he might use to work, that is, in what spaces of time, that he might not be hindered from preaching the Gospel, who can make out? Though, truly, that he wrought at hours of both day and night himself hath not left untold. [2518] Yet these men truly, who as though very full of business and occupation inquire about the time of working, what do they? Have they from Jerusalem round about even to Illyricum filled the lands with the Gospel? [2519] or whatever of barbarian nations hath remained …
St. Augustine—Of the Work of Monks.

Moreover, if Discourse must be Bestowed Upon Any...
21. Moreover, if discourse must be bestowed upon any, and this so take up the speaker that he have not time to work with his hands, are all in the monastery able to hold discourse unto brethren which come unto them from another kind of life, whether it be to expound the divine lessons, or concerning any questions which may be put, to reason in an wholesome manner? Then since not all have the ability, why upon this pretext do all want to have nothing else to do? Although even if all were able, they …
St. Augustine—Of the Work of Monks.