Matthew 17:8

and when they had lift up their eyes, they saw Jesus all alone.

Mark 9:8

and instantly looking round about, they did not see any other person but Jesus with them.

Luke 9:36

and before the sound was gone, Jesus was left alone: this they kept secret, and for some time did not acquaint any one in the least with what they had seen.

Acts 12:10-11

when they had pass'd the first and second guard, they came to the iron-gate that leads to the city, which open'd to them of itself: so they went out and pass'd together thro' one street: when all of a sudden the angel quitted Peter. Then coming to himself; now,

Treasury of Scripture Knowledge

Summary

And when they had lifted up their eyes, they saw no man, save Jesus only.

Bible References

They saw

Mark 9:8
and instantly looking round about, they did not see any other person but Jesus with them.
Luke 9:36
and before the sound was gone, Jesus was left alone: this they kept secret, and for some time did not acquaint any one in the least with what they had seen.
Acts 12:10
when they had pass'd the first and second guard, they came to the iron-gate that leads to the city, which open'd to them of itself: so they went out and pass'd together thro' one street: when all of a sudden the angel quitted Peter. Then coming to himself; now,