You probably don't need us to tell you that the stock front axles of your Suzuki Samurai are smaller than the rear ones. The fronts are 22-spline and the rears are 26-spline. If you'd like to use larger 26-spline aftermarket axle shafts in the front you need to replace your differential side gears.
Use these Side Gears from Low Range Off-Road to step up to larger, stronger front axles. Additionally they are ideal for locker upgrades that do not include their own side gears (e.g. Spartan Lockers or Lockrights). They are sold individually, so you'll need two to upgrade both front axles.
Stocking a spare or two might get you out of a bind someday and if nothing else... imagine the bargaining leverage you'll have over your less-prepared peers should a differential tragedy befall them!