That's what all the great mystics have been trying to tell us through the ages, as they witnessed to the unifying power of the divine love. Such knowledge does not come through intellectual arguments but through contemplative prayer.
God invites us into the conversation where we can speak and simply listen in the stillness of peace and grace. While one comes from the heart they other penetrates the heart. Either way, love begins and ends in the heart where it is united with all.
"The Spirit of Jesus allows us and invites us to see the heart of God, the heart of the universe, and our own hearts as one. It is in the heart of God that we can come to the full realisation of the unity of all that is, created and uncreated."
Quotes and inspiration by Henry Nouwen, Bread for the Journey (HarperCollins: 1997).