How does Calvinism explain Paul and Silas' response to the Philippian jailer and the "persuading" of men?

> And the keeper of the prison awaking out of his sleep, and seeing the prison doors open, he drew out his sword, and would have killed himself, supposing that the prisoners had been fled. But Paul cried with a loud voice, saying, Do thyself no harm: for we are all here. Then he called for a light, and sprang in, and came trembling, and fell down before Paul and Silas, And brought them out, and said, **Sirs, what must I do to be saved? And they said, Believe on the Lord Jesus Christ, and thou shalt be saved, and thy house.** - Acts 16:27-31 "What must I do to be saved?" is the question put to them. Isn't the Calvinist answer, "There is nothing that you can do ."? Paul and Silas answer, "Believe...and you will be saved.". Isn't the Calvinist answer, "You cannot believe unless God spiritually regenerates you first .". If Paul believed and taught Calvinism, why did he respond in a way that appears to give the jailer a decision to make? A background, related question would be, why, if Paul was Calvinist, did he expend effort in trying to persuade men? Persuade,in Koine Greek, means much the same as it does in modern English: cause (someone) to do or to believe something through reasoning or argument. How does Calvinism expound on this passage of Scripture and the notion of "persuading" men?