Everyone of the Messengers opened his Da'wah with the call to worship Allah (AWJ)

Everyone of the Messengers opened his Da'wah with the invitation to worship Allah, as is the saying of Nooh (SAAWS) and those who came after him in Surat Ash-Shu'araa and others,

Worship Allah! you have no other deity but Him. [Al-Moo-minoon:32]

In the "Musnad" upon Ibn 'Umar (RAA), upon the Prophet (SAAWS) who said, "I was sent between the hands of the Hour with the sword until Allah will be worshiped Alone with no partner, my sustenance was made under the shadow of my spear, and humiliation and lowliness were made for those who disobey my order." ⁽¹⁾