The most notable thing about this song may be that it features music legends Elton John on keyboards and David Crosby on harmony vocals. The song marks the first time Dylan ever collaborated with Elton. Crosby also sang harmony vocals on "Born in Time," another song on Under the Red Sky.
"2 x 2" is the second song on Side 2 of Under the Red Sky. It contains some Biblical allusions, with "two by two they stepped into the ark" being a clear reference to the story of Noah told in Genesis 6–9.
It seems like more a nursery rhyme than anything else. Some lyrics, such as "seven by seven they headed for heaven" and "nine by nine they drank the wine," suggest there's some deeper religious motif at play, but nothing particularly insightful or powerful emerges.
The whole of Under the Red Sky has generally been considered a miss by fans and critics alike. Over the years, some of the tracks have garnered a little more respect, but "2 x 2" isn't one of them. It's a forgettable track on a mostly forgettable album that Dylan himself didn't seem to take very seriously.