We cannot defend ourselves from the attack of the noontide devil except with the aid of noontide light. When the noontide devil sets our to tempt a person, there is no chance of parrying him; he will tempt and overthrow his victim by suggesting what appears to be good, by persuading us–unsuspecting and unprepared as we are–to commit evil under the guise of good, unless the Sun of heaven shines into our hearts with noontide brightness. The tempter, clothed in a certain splendor, really appears like the noon when he comes with the suggestion of an apparently greater good.
the Lord walking over the sea and took him for a ghost. Was not this cry of fear a sign that they mistook him for the noontide devil? Let us then be aware of this temptation. The greater perfection a person may have seem to have attained, the more he must be convinced to watch vigilantly for the actual noontide devil. He who was the true Noontide made himself known to the disciples with the words, it is I, have no fear; and their mistrust was dispelled. Whenever this painted falsehood tries to take us unawares, may the true Noontide shining from the heavens, send forth his light and his truth even to us. Let him divide the light from the darkness, lest we be numbered by the Prophet among those who put darkness for light and light for darkness.
from Bernard of Clairvaux’s Sermon 33 on The Song of Songs, CF 7, pp 152-156