Many Persians were Christians. Even more people in the Sassanid Empire were too. The Christian Armenians wrote in the Persian scripts for decades. Even the Persian scripts derive from the Semitic Syrian script and the Persians, especially the Sassanids were Orthodox Zoroastrians and didn't mind writing in the script of the heathens. Armenian alphabet is a mixture of Persian and Greek letters. The Arabs adopted their script from the Nabatean Arabs, who were Christians. The Arabic script was developed by Christians not Muslims. There is nothing strange about that.

I was under the impression that Arabic developed from the South Arabian script when Arabs adopted it and changed it into a connected script and developed a system of diacritics. What's your source on this?

According to that article, it was Arabs who invented the system of consonant dotting (اعجام) and vowel signs (حركات). So I'd say it was the Arabs who deserve credit for developing the alphabet into its final form, although it did derive from the Nabatean script. You are absolutely right about that.

Yes, but the first Arabs who wrote in it were pre-Muslim: Christians, Jews or Pagans.

Still, Delodephius, could you please specify and comment on the exact Armenian letters you find related in the table you published, let's have a closer look at them. And, please, would you tell the source of that table.

If you delve a bit into the history of Mashtots' creating the alphabet, you'll see that whole campaign was aimed at dissociating Armenia from Persia, whose official religion then was Mazdakism. All foreign scripts were banned in Armenia as soon as Armenian alphabet was created. Were the rulers of Armenia so silly to take Persian characters, label them "Armenian", and then ban the Persian alphabet proper? It was something completely different from Persian that the rulers of Armenia needed.

What I'd like to prove is that Semitic letters may be present in Armenian, but they're not necessarily of Persian origin. Also I'm not too convinced by the Armenian symbols in the table, what's the 4th Armenian from the bottom? Cannot recognize it...

Are you Armenian? Or do you have some anti-Persian agenda? That Armenian letters derive from Persian ones is a trivial matter to me, an interesting one, but nonetheless a trivial one, and yet now I'm suppose to bother myself in showing you something you are more than capable of doing yourself. Just take a piece of paper and draw Armenian and Persian letters from side by side and experiment a bit. I am in no mood nor am I interested enough to do it for you just because you asked.

I'm Ukrainian, that's neither anti-Persian, nor pro-Armenian. But I'm the kind of a person that respects close study of everything. There's no problem if you don't want to prove your point of view, but, please, don't you tell me my eyes see differently from your ones. Maybe the next thing you're going to say will be your skull proportions' measurements are different from mine? Until now your sole argument was "I can see it, and you cannot."

Disclose, at least, the source of the table.

You can find it here:
http://std.dkuug.dk/jtc1/sc2/WG2/docs/n3294.pdf

Delodephius, your hand writing is beautiful, you should do some more calligraphy. Honestly, I know very little about Persian scripts in general, but I just wanted to throw another voice in to say that I can very clearly see the connection between them and Armenian, more-so than what I can see between all the other scripts.