What is the meaning of Acts 21:31-36?

31 And as they went about to kill him, tidings came unto the chief captain of the band, that all Jerusalem was in an uproar. 32 Who immediately took soldiers and centurions, and ran down unto them: and when they saw the chief captain and the soldiers, they left beating of Paul. 33 Then the chief captain came near, and took him, and commanded him to be bound with two chains; and demanded who he was, and what he had done. 34 And some cried one thing, some another, among the multitude: and when he could not know the certainty for the tumult, he commanded him to be carried into the castle. 35 And when he came upon the stairs, so it was, that he was borne of the soldiers for the violence of the people. 36 For the multitude of the people followed after, crying, Away with him. (Acts 21:31-36 KJV)

William Burkitt’s Commentary

Note here, 1. How the great and gracious God provideth seasonable rescues for his persecuted and perplexed saints and servant: When they went about to kill Paul, God raises a deliverer for him. 

Note, 2. The unexpected instrument of the apostle’s deliverance was a heathen governor. The Romans never durst trust such vast multitudes at Jewish festivals without a strong garrison to be a check upon them; accordingly, the governor, having tidings of the tumult, brings down a band of soldiers, to see the peace kept; he rescues the injured apostle out of their hands, commands him to be bound with two chains, as Agabus had foretold, and the soldiers bear him up in their arms from the violence of the people.

Hence we learn, 1. That a bad government, even a heathenish government, is better than anarchy. Under a tyrannical government, many may be uneasy, but under popular rage none can be long at rest.

Learn, 2. That heathens are oftentimes the protectors of Christians against the blind rage of those that profess to worship the same God. St. Paul and these unbelieving Jews worshipped the same God, and yet the heathen soldiers were fain by force to carry and guard the apostle against the fury of the bloody unbelieving Jews.

Thus God raiseth up what instruments he pleases to subserve his own gracious ends and designs in the preservation of his people. The barbarous heathen soldiers protect St. Paul and keep him from being torn in pieces by the Jews, who worshipped the same God as him.