The inner heart and soul of every Jew needs “circumcision” to be expressed:[1]
On Rosh Hashanah Hashem makes a covenant with every single Jew. This covenant takes place between G-d and the inner recesses of one’s soul, connecting it to G-d. Now, although Rosh Hashanah is a time of awe and trepidation, nevertheless it is also time of revelation of inner love. However, this love remains in the inner recesses of the heart which is not expressed, as expressed in the verse “Vegilu Beriada/and one rejoices with trepidation.” Now, the reason why this connection is referred to as a Bris, covenant, is because it is not possible for it to be properly expressed unless one first removes the foreskin of the heart. Although certainly every single Jew contains this aspect within his soul, it is not possible to be expressed without the circumcision of the heart. How is the circumcision performed? Through removing one’s connection to worldly lusts and pleasures. One’s involvement in chasing after worldly lusts and materialistic fortunes creates a foreskin over one’s inner recesses of his heart which covers and conceals his love for G-d from being expressed and hides away his desire to attach to Him.
[1] Likkutei Torah p. 42a