(visual) witnessing, testimony
To officially become a Muslim, one performs this simple ritual. Normally, the affirmation is made aloud twice in the presence of at least one or two other Muslims.
أَشْهَد أَن لَا إِلَه إِلَّا الْلَّه و أَشْهَد أَن مُحَمَّد رَسُوْل الْلَّه
Lā ilāha illallāh wa-Muḥammad rasūl Allāh.
/lææ ʔɪlææhæ ʔɪllɑlˁlˁɑɑh mʊħæmmædʊ̃ rrɑsʊllʊlˁlˁɑɑh/
I testify that there is no god but God, and I testify that Muḥammad is God’s messenger.
- I vouch that there is none worthy of my worship but the Divine. And I vouch that Muḥammad was a communicator of the Divine (whose model I follow).
And of course you must actually believe it. Becoming a Muslim is is a lifelong commitment to worship Allāh. Before you can make this vow, you need to take the time to study Islam and educate yourself. Learn to pronounce the Shahādah and gain full understanding of its meaning. The affirmation must come genuine from the heart.
The moment somebody vows the Shahāhah, they begin with a clean slate. All past misdeeds are forgiven, and they begin their life as a Muslim.
what about ppl who grew up in Muslim tradition but never made a genuine shahadah of their own?
Faking the Shahādah
If somebody fakes the oath of Shahādah, e.g. they don’t fully believe it or don’t act accordingly, then that person is still technically a full member of the Muslim community. Only God can judge the sincerity of their belief.
Also, the word Shahādah, in a totally different context, means martyrdom.
Opposite of al-Ghayb
It's the Visible, the Observable, ....