LOL, what? Spanish "el" is etymologically derived from Latin ille/illa/illud, which became el/la/lo in Spanish.
Do you mean the sound combination "el", or the fact of having a definite article?
Latin did not have articles. The use of articles is a grammatical feature that has been borrowed between languages. But yes: that kind of borrowing is a lot less frequent than borrowing of vocabulary.
Why do you believe Spanish took "el" from Arabic?
Not always check Spanish for example they took a lot from Arabic, like 'EL'.