http://en.wikipedia.org/wiki/Sabellianism They do not believe that God is three in one. They believes that God, being omnipotent, can appear to humans in many forms, including becoming human like ...
From the answers to this question it seems that most if not all Jewish sources treat Trinitarian Christianity (in particular, their doctrine of the Trinity) as either Shittuf or outright Avoda Zara, ...
I recently heard that one is forbidden to get any benefit from a church (or any other place of worship other then a shul). They went on to say that the prohibation included while giving directions ...