When someone has resentment, ill-feeling or spite towards someone, they tend to hide it. They have a fake smile for you and fake salams.

When they are among their other friends they will talk about you but when they meet you it is all good. They pretend everything is fine. Allah calls them out on this.

Allah describes this as a disease of the heart. It is a spiritual disease. Allah questions them if they really think that they can hide this resentment and ill-feeling? Allah will bring out all forms of their resentment in one way or another.

If someone has upset you then you shouldn’t hide that. You shouldn’t arbor a grudge for that person and pretend everything is fine. You should be loving, transparent and honest. Don’t let it turn into a disease in your heart. Just let them know in a respectful way.