Comment vérifier si les e-mails existent dans Laravel Connexion

$validator = Validator::make($request->all(), [
        'email' => 'required|exists:users',
        'password' => 'required|string'
    ]);

    if ($validator->fails()) {
        flash('Email Does Not Exists')->error();
        
        // or 

        $request->session()->flash('message', 'Email Does Not Exists');
    }
Isaac