IV. In thinking upon God, we must put aside all material notions
When, therefore, we fix our minds on confessing the Father and the Son and the Holy Ghost, let us keep far from our thoughts the forms of things visible, the ages of beings born in time, and all material bodies and places. Let that which is extended in space, that which is enclosed by limit, and whatever is not always everywhere and entire be banished from the heart. The conception of the Triune Godhead must put aside the idea of interval or of grade, and if a man has attained any worthy thought of God, let him not dare to withhold it from any Person therein, as if to ascribe with more honour to the Father that which he does not ascribe to the Son and Spirit. It is not true Godliness to put the Father before the Only-begotten: insult to the Son is insult to the Father: what is detracted from the One is detracted from Both. For since Their Eternity and Godhead are alike common, the Father is not accounted either Almighty and Unchangeable, if He begot One less than Himself or gained by having One Whom before He had not.
Source: Sermons (New Advent)