Yesterday was Trinity Sunday, in which we reflect on the One true God who consists of three persons, the Father, the Son, and the Holy Spirit. That God is a unity of distinct persons means that we can accurately say that He is love, love being at the very essence of God, since love–even human love–can be defined as a unity of distinct persons. Christians worship the Triune God, a very different kind of deity from that of all other religions.
On Trinity Sunday, churches that follow the classic liturgy recite The Athanasian Creed. It begins like this:
Whosoever will be saved, before all things it is necessary that he hold the catholic faith. Which faith except every one do keep whole and undefiled, without doubt he shall perish everlastingly.
And the catholic faith is this, that we worship one God in Trinity, and Trinity in Unity; Neither confounding the Persons, nor dividing the Substance.