How was kaballah started and is it connected to the Torah? Is it real?

Why do different Rabbis say different things? Some of the Rabbis must be wrong then (Chash Beshalom) but some Rabbis say one thing and others say their opinion.

How do we know what Rashi says it true? How did he explain everything like he did?

dear rabbi many of the prayers in the siddur end with the phrase "aleinu val kol yisrael" why do we use this phrase and not mention the rest of the worlds population ? i know that ther are some prayers for the whole wrold on rosh hahsnah and yom kippur but am not aware of any others , do jews pray for the benefit of others or only jews? what are the reasons behind this? many thanks frank

Why do you put stones on headstones at a cemetary?