Internal attention is application or advertence of the mind.  Is such internal attention, such deliberate application or mental advertence necessary for the valid recitation of the office?

There are two opinions on this matter, two replies to the question.  According to one opinion, and this is the more common and the more probable one, internal attention is required for the valid recitation of the Hours. 1.  Because the Divine Office is a prayer, but there can be no true or real prayer without internal attention, for prayer is defined as an elevation of the soul to God, but if there be no internal attention, there is no elevation of the soul to God, and no prayer. 2.  Our Lord complained of those who had external attention at prayer, but lacked internal attention or advertence, “This people honour me with their lips, but their heart is far from me” (St. Matt. xv.). 3.  The Church appears to demand internal attention at prayer, for although she has not given any positive precept dealing with this kind of attention, she does the same thing when she commands that the recitation of the Divine Office take the form of prayer for God’s honour, and this recitation of words cannot be true prayer without internal attention. 4.  The Council of Trent seems to exact this attention when it wishes that the Divine Office be said reverently, distinctly and devoutly, reverenter, distincte, devote. 5.  If no internal attention be required in reciting the Hours, it is difficult to see how voluntary distractions are forbidden by Divine Law.

This is the opinion held by Cajetan (1496-1534), Sa (1530-1596), Azor (1539-1603), Sanchez (1550-1610), Roncaglai (1677-1737), Concina (1687-1756), and St. Alphonsus, the great Doctor of prayer (1696-1787).

According to the other opinion, external attention suffices always and ever to satisfy substantially the obligation of reading the office and for the avoidance of mortal sin which invalid recitation entails.  For,

(1) To pray is to speak to God, to trust in Him, to manifest to Him the wishes and wants of the soul; but this can be done by a person who has voluntary distractions of mind, just as a man can read to his king an address, setting forth the thanks and requests of his subjects, although the reader’s mind is far from dwelling on the words or the meaning of the sentences before his eyes.  But he is careful to read all the words in a clear, intelligible manner.  Now the theologians who maintain this opinion say that, a fortiori, this method of reading the Hours should be valid; for, in the reading the priest acts principally in the name of the Church, as her minister, and offers up prayers to God in her name, and they say that the irreverence of the servant does not render the prayer of the Church unpleasing to Him,

(2) He who makes a vow, and resolves to do a certain act, fulfils his vow, even when fulfilling it he acts with voluntary distractions; so, a pari, with the recitation of the office,