This "cheat" will give you 99999 health and armor, but saving or loading a game will reset the values to defaults. The default max for health/armor is 250.

How to get God Mode in Far Cry
Open devmode.lua in the Far Cry directory and add the following code to the bottom:

function GodMode()
if _localplayer then
_localplayer.cnt.health = 99999;
_localplayer.cnt.armor = 99999;
Hud:AddMessage(''[CHEAT]: Give 99999 health and armor'');
System.LogToConsole(''\001CHEAT: Give 99999 health and armor'');
else
Hud:AddMessage(''[CHEAT]: No godmode today'');
end
end

Now start the game using -devmode switch and bring up the console with the tilde (`/~) key.

Type in: #GodMode() and you're done! 9999 health + armor

Remember: saving or loading a game will restore the values.