Control from now and hereinafter (4)
I believe the answer is:
'control' is the definition.
(I know that rein is a type of control)
'now and hereinafter' is the wordplay.
'REIN' is hidden in amongst the letters.
But, I'm not sure how this is indicated.
'from' acts as a link.
Can you help me to learn more?
(Other definitions for rein that I've seen before include "kidney?" , "Horse's steering strap" , "leading article?" , "given free to experienced riders?" , "Part of a horses's harness" .)