But while we recognise the Three distinct Persons of the Trinity we do not forget their Unity in one God for where One is, there all Three are.

Thus speaking of the indwelling of the Holy Spirit Our Lord said, “…he abides with you, and he will be in you”, and then he went on to say, “Those who love me will keep my word, and my Father will love them, and we will come to them and make our home with them” (NRSV, John 14:17, 23).

Does this pass our understanding?  Of course, but then we are not expected to understand but to adore.  It is enough if we, like those early Christians, by our penitence and faith and love, experience the Blessed Trinity in our lives, for without that experience understanding is worthless.