Is it obligatory for a Muslim to pledge allegiance to a person by hand, following the example of the Companions with the Messenger and the Rightly Guided Caliphs?

The pledge of allegiance (bay'ah) is given to the Muslim ruler (wali al-amr) by the people of authority and influence (ahl al-hall wal-'aqd), who are the scholars and leading figures of the community. Through this pledge, his rule is established without the need for a general pledge from the common people themselves, who are then obligated to obey him in matters that do not involve disobedience to Allah. The pledge to the Imam has been mentioned in hadiths, such as the Prophet's (peace be upon him) saying: "Whoever dies without a pledge of allegiance on his neck dies a death of ignorance (jahiliyyah)," and "Whoever pledges allegiance to an Imam, giving him the clasp of his hand and the fruit of his heart, let him obey him as much as he can..." This pledge is not to be duplicated; it must be given to a single Imam. The pledge for men is by word and handshake, and for women, it is by word only, as the Prophet (peace be upon him) did.