A poem he wrote in 1960 titled Seven Stanzas at Easter reflects his piety. Updike makes the point that if one is a believer he/she should really believe. No wishy-washy liberal protestantism for him. The resurrection of Christ was either an actual, historical, physical return to life of a man who had been actually, historically, physically dead or else the whole story doesn't really matter at all.
None of this "Jesus' body actually, permanently decomposed, but he rose in the sense that his spirit lived on in the hearts of his followers" nonsense for Updike. Either it happened objectively or Christianity is a fraud.
About that he was surely correct.
Seven Stanzas at EasterBest wishes for a meaningful Resurrection Day tomorrow.
Make no mistake: if He rose at all
it was as His body;
if the cells’ dissolution did not reverse, the molecules
reknit, the amino acids rekindle,
the Church will fall.
It was not as the flowers,
each soft Spring recurrent;
it was not as His Spirit in the mouths and fuddled
eyes of the eleven apostles;
it was as His flesh: ours.
The same hinged thumbs and toes,
the same valved heart
that–pierced–died, withered, paused, and then
regathered out of enduring Might
new strength to enclose.
Let us not mock God with metaphor,
analogy, sidestepping transcendence;
making of the event a parable, a sign painted in the
faded credulity of earlier ages:
let us walk through the door.
The stone is rolled back, not papier-mâché,
not a stone in a story,
but the vast rock of materiality that in the slow
grinding of time will eclipse for each of us
the wide light of day.
And if we will have an angel at the tomb,
make it a real angel,
weighty with Max Planck’s quanta, vivid with hair,
opaque in the dawn light, robed in real linen
spun on a definite loom.
Let us not seek to make it less monstrous,
for our own convenience, our own sense of beauty,
lest, awakened in one unthinkable hour, we are
embarrassed by the miracle,
and crushed by remonstrance.