His execution wasn't humenary, they brived him the right to complite his to testmony (Shahada) as a right of any Muslim to say it before his/her death, the testemony says:
[I testify that ] there is no god (ilah) but God (Allah), and [ I testify that ] Muhammad is the messenger of God.
but he only said:
[I testify that ] there is no god (ilah) but God (Allah), and [ I testify that ] Muhammad...