heart and soul (
http://definr.com/heart and soul)
n : the choicest or most essential or most vital part of some
idea or experience: "the gist of the prosecutor's
argument"; "the heart and soul of the Republican Party";
"the nub of the story" [syn:
kernel,
substance,
core,
center,
essence,
gist,
heart,
inwardness,
marrow,
meat,
nub,
pith,
sum,
nitty-gritty]
adv : with complete faith; "she was with him heart and soul" [syn:
body and soul]