What is the meaning of Acts 24:17-21?

17 Now after many years I came to bring alms to my nation, and offerings. 18  Whereupon certain Jews from Asia found me purified in the temple, neither with multitude, nor with tumult. 19 Who ought to have been here before thee, and object, if they had ought against me. 20 Or else let these same here say, if they have found any evil doing in me, while I stood before the council, 21 Except it be for this one voice, that I cried standing among them, Touching the resurrection of the dead I am called in question by you this day. (Acts 24:17-21 KJV)

William Burkitt’s Commentary

Apostle Paul had vindicated himself from the charge and imputation of sedition and heresy before: he comes now to clear himself of the third charge, namely, the profanation of the temple; in order whereunto he declares that he had not been a long time at Jerusalem before this journey: and that he now came to bring alms to the poor Jews that were converted to Christianity: he acknowledges that at this time he went into the temple, yet not to profane it, but to perform those rites in it which the law of the Jews required of such as had the vow of Nazarites upon them. Thus the apostle cleared himself of all that was objected against him and made it evidently appear to the face of his enemies that all the accusations brought against him were false and clamorous.

Learn thence, That generally the accusations laid by the malicious to the charge of the innocent, are nothing but empty noise and clamour.

Having thus vindicated himself to their faces, he next appeals to the consciences of his accusers whether there was any relevant thing charged upon him more than that he professed and believed the resurrection of the dead.

Thus bravely did the apostle plead his own cause here, or rather the Spirit of God that spake in him, though Satan had got the high priest Ananias and his eloquent orator Tertullus to implead and impeach St. Paul; yet behold with what a flood of truth and eloquence does the apostle vindicate his own innocence.  Magna est Veritas & praevalebit: “Great is the truth, and will finally prevail.”