IT may be, my daughter, that you do not know how to practise mental
prayer, for unfortunately it is a thing much neglected now-adays. I
will therefore give you a short and easy method for using it, until
such time as you may read sundry books written on the subject, and
above all till practice teaches you how to use it more perfectly. And
first of all, the Preparation, which consists of two points: first,
placing yourself in the Presence of God; and second, asking His Aid.
And in order to place your self in the Presence of God, I will suggest
four chief considerations which you can use at first.
First, a lively earnest realisation that His Presence is universal;
that is to say, that He is everywhere, and in all, and that there is no
place, nothing in the world, devoid of His Most Holy Presence, so that,
even as birds on the wing meet the air continually, we, let us go where
we will, meet with that Presence always and everywhere. It is a truth
which all are ready to grant, but all are not equally alive to its
importance. A blind man when in the presence of his prince will
preserve a reverential demeanour if told that the king is there,
although unable to see him; but practically, what men do not see they
easily forget, and so readily lapse into carelessness and irreverence.
Just so, my child, we do not see our God, and although faith warns us
that He is present, not beholding Him with our mortal eyes, we are too
apt to forget Him, and act as though He were afar: for, while knowing
perfectly that He is everywhere, if we do not think about it, it is
much as though we knew it not. And therefore, before beginning to pray,
it is needful always to rouse the soul to a stedfast remembrance and
thought of the Presence of God. This is what David meant when he
exclaimed, “If I climb up to Heaven, Thou art there, and if I go down
to hell, Thou art there also!”  And in like manner Jacob, who,
beholding the ladder which went up to Heaven, cried out, “Surely the
Lord is in this place and I knew it not”  meaning thereby that he
had not thought of it; for assuredly he could not fail to know that God
was everywhere and in all things. Therefore, when you make ready to
pray, you must say with your whole heart, “God is indeed here.”
The second way of placing yourself in this Sacred Presence is to call
to mind that God is not only present in the place where you are, but
that He is very specially present in your heart and mind, which He
kindles and inspires with His Holy Presence, abiding there as Heart of
your heart, Spirit of your spirit. Just as the soul animates the whole
body, and every member thereof, but abides especially in the heart, so
God, while present everywhere, yet makes His special abode with our
spirit. Therefore David calls Him “the Strength of my heart;”  and
S. Paul said that in Him “we live and move and have our being.” 
Dwell upon this thought until you have kindled a great reverence within
your heart for God Who is so closely present to you.
The third way is to dwell upon the thought of our Lord, Who in His
Ascended Humanity looks down upon all men, but most particularly on all
Christians, because they are His children; above all, on those who
pray, over whose doings He keeps watch. Nor is this any mere
imagination, it is very truth, and although we see Him not, He is
looking down upon us. It was given to S. Stephen in the hour of
martyrdom thus to behold Him, and we may well say with the Bride of the
Canticles, “He looketh forth at the windows, shewing Himself through
the lattice.” 
The fourth way is simply to exercise your ordinary imagination,
picturing the Saviour to yourself in His Sacred Humanity as if He were
beside you just as we are wont to think of our friends, and fancy that
we see or hear them at our side. But when the Blessed Sacrament of the
Altar is there, then this Presence is no longer imaginary, but most
real; and the sacred species are but as a veil from behind which the
Present Saviour beholds and considers us, although we cannot see Him as
Make use of one or other of these methods for placing yourself in the
Presence of God before you begin to pray;–do not try to use them all
at once, but take one at a time, and that briefly and simply.
 Ps. cxxxix. 7.
 Gen. xxviii. 16.
 Ps. lxxiii. 26.
 Acts xvii. 28.
 Cant. ii. 9.