[Ali Imran]

Allah only ask for one shahada..who ask for the 2nd shahada? You declare the first part to God and the 2nd one to man...you are playing them on equal terms..

Quran 3:18, part of Surah Ali 'Imran, is considered a Shahada, or declaration of faith, in Islam. This is the true shahada...nothing else should be added

God bears witness that there is no deity except Him, and [so do] the angels and those of knowledge who uphold justice: 'There is no deity except Him, the Almighty, the All-Wise.'" (Quran, 3:18)

Allah also says Muhammad صلي الله عليه وسلم is the messenger, and we affirm it in the second shahadah.