The Washington Post provides background on Robert Jeffress.
Mitt Romney summed it up well:
Trump is a bigot and associates with bigots. This was a terrible choice.
Sad!
Update: More on Jeffress and Rev. John Hagee
The article states: “A Dallas evangelical pastor who once said that Jewish people are going to hell and a megachurch televangelist who claimed that Hitler was part of God’s plan to return Jews to Israel both played prominent roles on Monday in the opening ceremony of the new American Embassy in Jerusalem.”