Did the Prophet (peace be upon him) and Abu Bakr Al-Siddiq seeking help from the tribes constitute a specific act applicable only to them, making it unlawful for us to follow, and what is the proof of this specificity?

At all times and in all places, callers to Islam should emulate the Prophet (peace be upon him) in presenting Islam to individuals and tribes and seeking their support. This act is not exclusive to him; rather, it is a means to establish the religion of Allah. Allah Almighty says: "There has certainly been for you in the Messenger of Allah an excellent pattern."