The reason for the pairing of the two testimonies in a single pillar

Question:
Why were the two testimonies paired in a single pillar of the pillars of Islam, even though the intended meaning is two: the oneness of worship for Allah, and the messengership for Muhammad?

Answer:
Both are necessary; the two testimonies are obligatory. However, the station of the testimony of the oneness of Allah is greater, more important, and larger, because many people do not find it difficult to say: "Muhammad is the Messenger of Allah," and they acknowledge the messengership, but they do not apply the meaning of "There is no god but Allah." Therefore, the brothers drew attention to this word through the testimony contained in it, and further attention will be given to the testimony that Muhammad is the Messenger of Allah in other seminars.
But this word is with all the messengers, not with Muhammad alone. It is with Noah, with Adam, with Hud, with Salih, with Ibrahim, with Lut, and with the prophets after them: Musa, Harun, Isa, Dawud, Sulayman, and other messengers and prophets. This... so establishing this is something that has been necessary from the time of Adam until this day. It is necessary to establish "There is no god but Allah," to know its meaning, to fulfill its right, and to be sincere in worship to Allah alone in every age, from the time of Adam until this day.
And upon the Ummah of Muhammad (peace and blessings be upon him), in addition to that, is to believe in Muhammad (peace and blessings be upon him) along with the rest of the messengers. Just as it was upon those who were in the time of Adam, since our father Adam (peace be upon him) was a prophet sent to them, a messenger to them, and they took upon themselves his Shari'ah. Just as it was upon those who were in the time of Noah to believe in Noah along with the oneness of Allah. And upon those who were in the time of Hud to make Allah one, to believe in Hud, and to follow his Shari'ah. And so on, those who were in the time of Salih would make Allah one, believe in this word, believe in Salih in what he brought, and follow his Shari'ah. And so on, those who were in the time of Ibrahim, the time of Lut, the time of Musa, Harun, and others. Every Ummah is obligated to believe in its messenger along with the oneness of Allah, and along with sincerity to Allah.
And upon the last Ummah, the Ummah of Muhammad (peace and blessings be upon him), is to make Allah one, and to believe in their messenger Muhammad (peace and blessings be upon him) and submit to his Shari'ah. Both are necessary; the two testimonies are obligatory. One does not suffice in place of the other. If one makes Allah one and worships Him alone, and leaves off sins, but does not believe that Muhammad is the Messenger of Allah, then he is a disbeliever, and his blood and wealth are lawful according to all scholars. If one believes in the Messenger (peace and blessings be upon him) and affirms him, saying: "He is the Messenger of Allah," but does not come with the meaning of "There is no god but Allah," does not worship Allah, but worships others alongside Him, or curses Allah, or does what necessitates the nullification of his Islam, then his testimony that Muhammad is the Messenger of Allah does not benefit him. Therefore, the two testimonies are necessary, and it is necessary to establish them and act according to their implications, and then to act upon the prayer, the zakah, and so on.