_Invocation and Conclusion_. Prayer is addressed generally to God the Father. This practice is in accordance with the example and doctrine of Christ, "Father, I give Thee thanks" (St. John, xi, 41); "Amen, amen, I say to you; if you ask the Father anything in My name, he will give it to you" (St. John, xvi. 23). "And He taught us to say 'Our Father.'" In the early ages of the Church, seldom was prayer addressed to God, the Son. Innocent III. tells us that the reason for the practice was a fear that such prayer might lead the catechumens, the Jews or the Pagans converted to Christianity, to allege or to believe that Christians worshipped several Gods. However, with the advent of the early heresies, it became necessary to formulate prayers witnessing the divinity of Christ and His equality in all things to the Father and the Holy Ghost. In some of the great prayers of the liturgy, the three Persons of the Holy Trinity are named to show their equality and unity of nature and substance. Nearly all the prayers of this kind are the products of the Church during the storms of early heresy against the divinity, nature or personality of Christ. The conclusions of the prayers generally contain the words _Per Dominum nostrum Jesum Christum_, because all graces come through Jesus Christ, our Lord and Saviour, Who pleads, as Mediator between God and Man, as He Himself has said, "No man cometh to the Father but by Me" (St. John, xiv. 6). Hence, in every collect, we may distinguish five parts: the invocation, the motive, the petition, the purpose, the conclusion. (1) The Invocation takes some form such as _Deus, Domine_. (2) The motive is commonly introduced by the relative _qui_; e.g., Deus, _qui corda fidelium sancti spiritus illustratione docuisti_. (3) The petition, the body or centre or substance of the prayer, is always noted for the solemn simplicity of language, which marks liturgical prayer, e.g., _Multiplica_ super nos misericordiam tuam. (4) The purpose is an enforcement of the petition. It has reference, generally, to the need of the petitions and is marked usually with the word _ut_. "Multiplica super nos misericordiam tuam, _ut_ quae, nobis agendis praecipis, te miserante adimplere possimus" (prayer for feast of St. Patrick). (5) The _conclusion_ varies, e.g., "Per Dominum nostrum," "Per eundem Dominum," etc.