Advice of Scholars - WÂJIB AL-WUJÛD
‘Wujûd’ means ‘existence, being. ’ There are three kinds of existence. The first one is Wâjib al-wujûd, the Necessary Existence. He always exists. He has never been nonexistent before, nor will He stop existing in the everlasting future. Only Allâhu ta’âlâ is Wâjib al-wujûd.
The second one is mumtani’ al-wujûd, that cannot exist. It should never exist. Such is sharîk al-Bârî’ (partner to Allâhu ta’âlâ). Another god partner to Allâhu ta’âlâ or likeness to Him can never exist.
The third one is mumkin al-wujûd, that may or may not exist. So are the universe, all creatures without any exception. The opposite of wujûd is ’adam (non-existence). All creatures were in ’adam, were nonexistent, before they came into existence.