What did Voldemort say to Snape before killing him?

Voldemort told Snape he had been a faithful servant, but that he had to regrettably kill him, as he mistakenly believed he was the master of the Elder Wand, as Snape had killed Albus Dumbledore, its former owner the year prior, during the Battle of the Astronomy Tower.

Why did Snape fight Quirrell?

Once Voldemort learned that the Stone had been removed to Hogwarts School of Witchcraft and Wizardry, he conspired with Quirrell to steal it from the school. As Dumbledore was suspicious of Quirrell, he had tasked Severus Snape with keeping an eye on the latter.

How did Voldemort convince Quirrell?

Voldemort was able to attach himself to Quirrell when he failed to wash his hands after using a public lavatory.

Why didn’t Voldemort kill Snape as soon as possible?

Snape wasn’t even pretending to be a double agent during Philosopher’s Stone, so why Voldemort didn’t kill Snape as soon as he was physically able, or have Quirrell attempt to kill him, is unclear. So yes, why didn’t Voldemort suspect Snape as a double agent during the events of Philosopher’s Stone?

Why did Voldemort keep the Quirrell stone?

Voldemort must have thought that Snape didn’t know Voldemort was inside the body of Quirrell, He just had to keep the stone safe, because he wouldn’t get trusted by dumbledore.

Why didn’t Snape turn to Dumbledore for the Quirrell stone?

Ultimately though, had Snape, from Voldemort’s perspective, truly considered Quirrell an objective danger to Dumbledore’s plans for the stone, Snape would have turned to Dumbledore. Instead, Snape seems to be pursuing this on his own, which logically means Snape isn’t looking out for Dumbledore’s plans, but his (Snape’s) own plans.

How many times did Snape attack Quirrell in Harry Potter?

Snape cornered Quirrell more than once (Halloween, when Quirrell let the troll in, and the night Harry broke into the Restricted Section over the Christmas holidays to look for information on Nicholas Flamel) and openly threatened him against working for Voldemort and pressuring him to declare his loyalties to Dumbledore.