_I cried to the Lord with my voice, with my voice I made supplication to the Lord._[198] Prayer is of two kinds: public and private. _Public_ or common prayer is that which is offered to God by the Church's ministers in the person of the whole body of the faithful. And it is necessary that such prayer should be known to the body of the faithful for whom it is offered; this, however, could not be unless it were vocal; consequently it is reasonably enacted that the Church's ministers should pronounce such prayers in a loud voice so as to reach the ears of all. _Private_ prayer, on the contrary, is that which is offered by private individuals, whether for themselves or for others; and its nature does not demand that it should be vocal. At the same time, we can use our voices in this kind of prayer, and this for three reasons: Firstly, in order to excite interior devotion whereby our minds may, when we pray, be lifted up to God; for men's minds are moved by external signs--whether words or acts--to understand, and, by consequence, also to feel. Wherefore S. Augustine says to Proba[199]: "By words and other signs we vehemently stir ourselves up so as to increase our holy desires." Hence in private prayer we must make such use of words and other signs as shall avail to rouse our minds interiorly. But if, on the other hand, such things only serve to distract the mind, or prove in any way a hindrance, then we must cease from them; this is especially the case with those whose minds are sufficiently prepared for devotion without such incentives. Thus the Psalmist says: _My heart hath said to Thee, My face hath sought Thee[200];_ and of Anna we are told that _she spoke within her heart_.[201] And secondly, we make use of vocal prayer in payment, as it were, of a just debt--in order, that is, to serve God with the entirety of what we have received from Him; consequently not with our mind alone but with our body as well; and this, as the Prophet Osee says, is especially suitable to prayer considered as a satisfaction for our sins: _Take away all iniquity and receive the good, and we will render the calves of our lips_.[202] And thirdly, we sometimes make use of vocal prayer because the soul overflows, as it were, on to the body by reason of the vehemence of our feelings, as it is written: _My heart hath been glad, and my tongue hath rejoiced_.[203] But it seems to some that prayer should not be vocal, thus: 1. Prayer is, as we have said, principally directed to God, and God knows the heart's speech. Consequently to add vocal prayer is idle. But vocal prayer is not employed in order to manifest to God something which He did not know, but to stir up the mind of him who prays, and of others, too, towards God. 2. Again, man's mind is meant to rise by prayer towards God; but words, and other things pertaining to the senses, keep back a man from the ascent of contemplation.