I think that Paul shook off the snake that bit him into the fire (Acts 28) because he knew: (1) that God would not have brought him through severe persecutions, mindless hatred, assassination attempts, harsh beatings, imprisonments, whippings and numerous shipwrecks only to allow him to die from a bite by a satanic symbol.
Paul knew (2) that he would soon arrive at the seat of Roman power and authority and see fulfilled the promise by Jesus that he must — that’s an imperative! — witness to Caesar (Kaiser, Czar: same title, other languages).
Paul knew (3) that there was still more in him than he’d had time to share during years of ministry and church building and perhaps instead write some letters to churches rather than travelling.
Maybe Paul also knew (4) that the thought of ending his apostolic ministry so ignominiously by — of all things — a snakebite, would have been contrary to the onward and upward call of Jesus Christ in his life.
Notice that I prefaced the above with “I think”, but this is because it is based on five decades of preaching, teaching and world travel, and some experiences of very real danger during those decades. It is the nature of younger ministers to dismiss the possibility of ongoing ministry by ministers my age but it’s a mistake.
God’s Word says, “As your days, so shall your strength be.” This is not a promise of endless life and strength but of as much life and strength as will be required to finish the course, keep the faith, and complete the Divine call.
Watch this space.