The best way to see it is to perform the no weapon glitch and pick up the bomb, walk to a wall and hold R so the bomb is quickly bouncing between you and the wall. If this does not work because the wall is too light/the bomb is too much to one side of the screen then look directly up and hold R and you can see it as its thrown into the air. Also, it helps to use a Spartan player, as opposed to an Elite, because the dropping animation is different. This difference means that the bomb drops directly down, not forward first.
An alternate method is to simply grab the bomb and to drop it into a shiny area of the map, and then zoom to focus at the bottom of the bomb with a Sniper/Beam rifle. The messages are much more visible in these conditions.
Halo 2 Messages
The messages seem to correspond to what map is used:
'Thus I Refute Thee':
- Ivory Tower
- On Bungie.net's matchmaking stats section of the service record, the description of the bomb is "Thus I refute thee."
'Hold Onto Yer Butt':
'Kiss It Goodbye':
A hieroglyph of a Spartan helmet, the two fingered peace symbol followed by "xoxo ♥":
Halo 3 Messages
Which message you see depends on one thing: whether or not you are the Connection Host. If you are, the message you see is "Hold Onto Yer Butt." If you are not the connection host, the message you see is "Thus I Refute Thee."