How does sin destroy us?

Sin does not have the power to destroy you. It can only impede, retard and delay you on your evolutionary journey. Sin can only hold you back and force you to spend more lives than are necessary in material bodies.

Sin occupies but a narrow space in life.

It cannot go beyond the point where self-consciousness is born, nor can it mount to that height of spiritual enlightenment to which your evolution soon carries you.

Sin is eventually a corrective force.

It eventually pushes you toward the good by forcibly revealing to you the fact that you are out of harmony with the good or with Nature or with the purpose of life.