What is the ruling on buying gasoline from an Arab person who sells it at a slightly lower price, even with the suspicion that it is stolen, especially since the cost of living and gasoline are expensive in the foreign country of residence?

If it is merely a doubt or an illusion that the man is stealing gasoline, then the original ruling is that it is permissible to buy from him, because the basic principle concerning a Muslim is their integrity. As Shaykh al-Islam Ibn Taymiyyah said: “The unknown is like the non-existent, and the basic principle concerning what is in the possession of a Muslim is that it is their property if they claim it as such.”