“I believe because it is absurd” is a paraphrase of a statement in Tertullian’s work De Carne Christi (written between AD 203-206) “prorsus credibile est, quia ineptum est”, which can be translated: “it is by all means to be believed, because it is absurd”. The context is a defence of the tenets of orthodox Christianity against docetism:
Crucifixus est Dei Filius, non pudet, quia pudendum est;
et mortuus est Dei Filius, prorsus credibile est, quia ineptum est;
et sepultus resurrexit, certum est, quia impossibile.
— (De Carne Christi V, 4)
“The Son of God was crucified: there is no shame, because it is shameful.
And the Son of God died: it is by all means to be believed, because it is absurd.
And, buried, He rose again: it is certain, because impossible.”
Tertullian has been called ‘the father of Latin Christianity’ and ‘the founder of Western theology’. He is the first to use the word “Trinity” in reference to God.
‘the Son of God died: it is by all means to be believed, because it is absurd.’
Muslims been saying it is absurd for years too.