"Linguistically, it is certainly possible to support the rendering "Yahweh our God is one single Yahweh"; that is to say, he is not a God who can be split up into various divinities or powers, like the Baals of Tyre, of Hazor and or Schechem, etc., but one who unites himself as a single person everything which Israel thought of as appertaining to God." (Theology of The Old Testament)
The Biblical data clearly indicates that Yahweh or God exists as one personal Spirit being (Ps. 139:7-12; Isa. 31:3; John 4:24) who is invisible (Deut. 4:11-15; Job 9:11; 1 Tim. 6:15-16) omnipotent (Gen. 17:1; 18:14; Ps. 135:5-6), omniscient (Gen. 6:5; 1 Kings 8:39; Job 37:16), self-existent (Ex. 3:14; Isa. 43:10, 44:6; Jer. 10:10) who is personal enough to think and know (1 Sam. 2:3; 1 Chron. 28:9; Job 28:20-24), to create plans and act upon them (Isa. 14:26-27, Isa. 46:10; Isa. 55:11) make judgements (Prov. 5:21; Jer. 20:12) feels emotion (Gen. 6:6; Deut. 32:35-43; Job 19:11)) and respond to others (Ex. 3:7, 6:5; Job 34:28; Ps. 81:19).
Such things are true statements of what should be both the Jewish and Christian creed. This is not to deny that there are certain irreconcilable differences (between Judaism and Christianity) but it is to affirm, for the sake of this discussion, that Yahweh is one. This unchanging creed should help us govern our understanding of the majesty and might of the undivided True and Living God. There is no reason to suppose that the Shema includes a reference to the being of God but not His person. In light of the Incarnation this understanding does not change but further affirms that God is truly one and that one God has been manifest in the flesh. Jesus is that God manifest in flesh.