en_tn/jer/11/20.md

the heart and the mind

The heart is a metonym for what a person feels and desires and "the mind" is a metonym for what a person thinks and decides. Alternate translation: "a person's feelings and thoughts" (See: rc://en/ta/man/translate/figs-metonymy)

I will witness your vengeance

The word "vengeance" here can be expressed as a verb. Alternate translation: "I will watch you take revenge" (See: rc://en/ta/man/translate/figs-abstractnouns)