Get the post content by post title or post slug

Question

I will be short and direct.

I'm trying to take the post content in wordpress just by using the post title or slug. I found something that can help me but i don't want to use the id of the post, just the title or the slug.

Then, i want to show the thumbnail of the required post by slug/title in two different column.

I hope i was very explicit in my description.

Thanks in advance.