Help me find the manga!

It's a black and white manga where the mc is a little boy, he's been reincarnated and can use magic. I think he's been blessed by a god/has divine powers (?). He has white hair. There was one scene where he creates a rainbow but is then scolded by his father because it represents god (or smthing along those lines) and after that his older brother comes rushing in, his older brother has brown hair. It's then found out that the brother had been skipping out on his studies. He is told not to create rainbows again. Thank you <3