I dont know who wrote this, but it’s brilliant. 
1. Onward, Emacs coders, marching as to war, with the cross of Stallman going on before. Gnu, the royal Master, leads against the foe; forward into battle see his banners go! (Meta-x-Refrain): Onward, Emacs coders, marching as to war, with the cross of Stallman going on before. 2. At the sign of triumph Vi's host doth flee; on then, Emacs coders, on to victory! Vi's foundations quiver at the shout of praise; brothers, lift your voices, loud your anthems raise. (Refrain) 3. Like a mighty army moves the church of Gnu; brothers, we are treading where the FSF have trod. We are not divided, all one body we, one in hope and doctrine, one in charity. (Refrain) 4. ed and EVE may perish, TECO rise and wane, but the church of Stallman constant will remain. Gates of vi can never against that church prevail; we have the Gnu's own promise, and that cannot fail. (Refrain) 5. Onward then, ye people, join our happy throng, blend with ours your voices in the triumph song. Glory, laud, and honor unto Gnu the King, this through countless ages men and lispers sing. (Refrain)
See also The accompanying flag.