Between meetings yesterday, I did what I often do not head for a cafe to furiously beat my thumbs against my Blackberry in answer to the call of the myriad e-mail - they can wait - but step a moment into the National Gallery and find a picture.
Sometimes this is a random of gift of circumstance, sometimes it is a straight line towards a given favourite. It was the latter yesterday and Piero della Francesca's 'The Baptism of Christ'. This was originally designed as an altarpiece for a church in Sansepolcro, Piero's hometown.
The baptism takes place in a Jordan river of the painter's imagination and within the painter's place - the hills in the background are the Umbrian hills. The baptism is an event eternalising time - it is both an historical moment and one that is now and for ever. It can present itself anywhere and invites itself into our narrative now and here.
The symbolism of the painting is duly complex as was the beloved pattern of the Renaissance and of Piero's own practice. Piero was also a mathematician of note and his beautifully cool and balanced paintings are highly wrought images woven on a weft of geometry and number.
History too plays its part - the walnut tree that shelters Christ is not only an image of the crucifixion but also plays a part in the sacred history (literal or imagined) of Sansepolcro itself.
It was in the Renaissance (at its best) when the twin demands of eternity and time were perfectly balanced - this world was a celebrating image of another world neither merely an arduous waiting room for the main event in heaven or in hell nor the only world, time bound and temporary.
Yesterday, I was most drawn towards the three accompanying angels to the left. The middle angel's expression seems full of concern for what is to come, what the acceptance of baptism means in terms of crucifixion, the outlying angels appear to turn towards him with a compassionate concern. This is the taking on of a wound, a rift in the eternal patterning, that will be a blessing and a healing.
The three angels, of course, are an 'Old Testament' foreshadowing of the Trinity, symbolising God's presence, so here God looks upon his reflecting self, fully embedding in humanity, returning humanity to its full imaging of, in God.
The painting, even in the bustle of the National Gallery, manages to compose calm about it, a contemplative moment in a busying day.