John Cassian, Conferences I–X I.15: How we must meditate on God

But the contemplation of God is gained in a variety of ways. For we not only discover God by admiring His incomprehensible essence, a thing which still lies hid in the hope of the promise, but we see Him through the greatness of His creation, and the consideration of His justice, and the aid of His daily providence: when with pure minds we contemplate what He has done with His saints in every generation, when with trembling heart we admire His power with which He governs, directs, and rules all things, or the vastness of His knowledge, and that eye of His from which no secrets of the heart can lie hid, when we consider the sand of the sea, and the number of the waves measured by Him and known to Him, when in our wonder we think that the drops of rain, the days and hours of the ages, and all things past and future are present to His knowledge; when we gaze in unbounded admiration on that ineffable mercy of His, which with unwearied patience endures countless sins which are every moment being committed under His very eyes, or the call with which from no antecedent merits of ours, but by the free grace of His pity He receives us; or again the numberless opportunities of salvation which He grants to those whom He is going to adopt—that He made us be born in such a way as that from our very cradles His grace and the knowledge of His law might be given to us, that He Himself, overcoming our enemy in us simply for the pleasure of His good will, rewards us with eternal bliss and everlasting rewards, when lastly He undertook the dispensation of His Incarnation for our salvation, and extended the marvels of His sacraments to all nations. But there are numberless other considerations of this sort, which arise in our minds according to the character of our life and the purity of our heart, by which God is either seen by pure eyes or embraced: which considerations certainly no one will preserve lastingly, if anything of carnal affections still survives in him, because “thou canst not,” saith the Lord, “see My face: for no man shall see Me and live;” viz., to this world and to earthly affections.