Because of this, the horn-blasts te-qi’ah, she-varim, and te-ru’ah are the means of their smashing, and of them it is stated: (Ps. 89:16) Happy is the nation, those who know the te-ru’ah, Y”Y, they shall walk in the light of Your face. What is... Your face? These are te-qi’ah, she-varim, te-ru’ah, which are: te-qi’ah – the white of the face, she-varim – the red of the face, te-ru’ah – the green of the face. And through it te-ru’ah Israel emerges from exile, when the faces of Israel are transformed to green, like a pregnant woman.lxiiiSee BT Sanhedrin 98b