How did the petition of right protect a person who is arrested

The Petition of Right was made to prevent the king from arresting whoever he wanted. For the king to arrest someone he needed a cause.

The Petition of Right, initiated by Sir Edward Coke, was based upon earlier statutes and charters and asserted four principles: no taxes may be levied without consent of Parliament; no subject may be imprisoned without cause shown (reaffirmation of the right of habeas corpus); no soldiers may be quartered upon the citizenry; martial law may not be used in time of peace.