I remember a quote saying "you aren't your thoughts". Is that close?
It doesn't help me, but I have a pretty healthy sense of who I am. Someone who is having thoughts of suicide or of killing others, yeah, I would tell them that. But it's not that simple. We don't know what thoughts are, but we know they can occur randomly. That is, there isn't a thought generating mechanism that you can get control of. You can influence your environment and that will affect your thoughts, but there is no direct mechanism.
That works both ways, you can have a thought that comes out of nowhere, then choose to dismiss it if you like. You can read a subject, observe it in action, listen to the ideas of others, and then you might think something valuable that didn't seem to come from any of those sources. You can choose to follow that thought.