What is the evidence for looking at the place of prostration in prayer?

Question:
Is there an authentic hadith regarding looking at the place of prostration in prayer?

Answer:
All I recall is the prohibition against raising the gaze; a warning was issued against raising the gaze.
Q: So what is the recommended practice?
A: It is obligatory to lower the gaze; the warning against raising the gaze to the sky indicates that it is obligatory to lower it.
Q: Looking at the front?
A: The recommended practice is to look at the place of prostration; because it is closer to humility.
Q: During the bowing and during the tashahhud, is there anything that specifies where the gaze should be directed?
A: I do not recall anything on this, and the intention is to do what is closer to humility.