IV. The foolish practice of some who turn to the sun and bow to it is reprehensible
From such a system of teaching proceeds also the ungodly practice of certain foolish folk who worship the sun as it rises at the beginning of daylight from elevated positions: even some Christians think it is so proper to do this that, before entering the blessed Apostle Peter's basilica, which is dedicated to the One Living and true God, when they have mounted the steps which lead to the raised platform, they turn round and bow themselves towards the rising sun and with bent neck do homage to its brilliant orb. We are full of grief and vexation that this should happen, which is partly due to the fault of ignorance and partly to the spirit of heathenism: because although some of them do perhaps worship the Creator of that fair light rather than the Light itself, which is His creature, yet we must abstain even from the appearance of this observance: for if one who has abandoned the worship of gods, finds it in our own worship, will he not hark back again to this fragment of his old superstition, as if it were allowable, when he sees it to be common both to Christians and to infidels?
Source: Sermons (New Advent)