heart and soul

Noun	1.	heart and soul - 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" Synonyms: essence, inwardness, nitty-gritty, gist, pith, substance, meat, nub, kernel, core, sum, center, heart, marrow
Adv.	1.	heart and soul - with complete faith; "she was with him heart and soul" Synonyms: body and soul