One of the coolest things about the isomorphism theorems and something not everyone seems to remember is that they were first formulated (at least
explicitly) by
Emmy Noether. Indeed, some people refer to these as "Noether's isomorphism theorems". They are very characteristic of her work and her methods.
In the words of one of Noether's colleagues P. S. Alexandroff, in her approach to algebra she
"taught us to think in simple, and thus general terms... homomorphic images, the group or ring with operators, the ideal... and not in complicated algebraic calculations,"
which is exactly what the isomorphism theorems are -- simpler terms. Next time you quotient an algebraic structure by the kernel of some homomorphism, remember Noether.