How were Moses and Jesus seen at the same time?

I forget the exact chapter where this happens in NT. Jesus is with Peter and 1 or 2 of the other Apostles and they're hiking around some mountain. They stop to rest for awhile, then Jesus starts climbing up towards the summit. When he gets to the top he starts praying for a while and then all the sudden a neon white glow appears all around the top of the mountain. It gets so bright that Peter and the others have to look away for a second, then when they turn back Moses and Ezekiel are both up on the summit with Jesus. They're wearing clothes that have the same brilliant white glowing that just flooded the mountaintop. After being completely astounded by this, Peter decides to go up and offer his tent to Moses and another Apostle offers his to Ezekiel, if they want to set up camp and stay the night. Jesus or Moses I can't remember which chuckles at this and then the prophets both tell him Jesus is the Savior and to listen to him. Then the intense white light returns and they're gone.