Does one who enters prayer without khushu' or presence of heart have to repeat it?

Question:
May Allah reward you. In his other question, he asks: What is the ruling on one who enters prayer while thinking about worldly matters, and at times does not realize he is in prayer until after he has said the taslim? Is his prayer valid, or does he have to repeat it, or what should he do? Please inform us. May Allah reward you with good.

Answer:
This is a lack of khushu' in prayer, and khushu' is the spirit and essence of prayer. So he must treat himself by returning to his prayer and keeping the greatness of Allah the Exalted in his mind, and he must not persist with the whispers of Shaytan or with thinking about worldly matters. If he does not pay attention and continues with these thoughts in his prayer, and remains preoccupied with worldly affairs...
...then he has nothing from his prayer except what he understood of it and in which his heart was present. He may have half a prayer, a quarter of a prayer, a tenth of a prayer, or he may have nothing at all. But he is not ordered to repeat it; because he prayed in appearance, he is not ordered to repeat it. Yes.