It's unfortunate that discussions of this nature are hijacked by the rabid anti Arab lobby that consistently uses sect mentality to demonish and attack Arabs. For your info, Iran is openly recruiting Pakistani citizens and sending them to the deathbeds in Iraq, Syria and Yemen. This while being the nerve center for Indian spies and machinations against Pakistan. Recent arrest of the high ranking Indian general arrested by the ISI should suffice. If this is not enough, Iran is hosting your biggest enemies at Chabahar strategically undercutting CPEC.
The Iranian fanboys above conveniently ignore this because addressing these issues destroys the ideological basis these arguments are derived from.
With or without Arabs, Iran is a mortal enemy of Pakistan. The Arabs are more than enough to defend themselves. It's Pakistan that needs to be worried about Iran's designs for the long run.