Praying to God vs. praying to others

Often, our Protestant brothers and sister in Christ become at least uncomfortable, or otherwise downright objectionable, when the subject of praying to the saints comes up. I think the controversy comes back to the definition of prayer. Many people equate prayer with worship. If that is the case, then prayer to the saints would certainly be forbidden. However, "pray" (which essentially means "to ask") is not the same as "worship," though given the frequency with which prayer takes place in worship, I could understand the confusion. St. Thomas Aquinas has the following to say about the subtle distinction between praying to God and praying to others.

According to God's providential design, everything which exists is given the means to attain the end befitting its nature. Human beings too, in order to obtain what they hope for from God, have received a means adapted to the human condition. This condition obliges us to use a humble form of request or prayer to obtain what we hope for from others, especially if the person addressed is our superior. For this cause people are exhorted to pray in order to obtain from God those things which they hope to receive from him. But the requisite prayer is different according to whether it is a question of obtaining something from another person or from God.

When a request is addressed to a person, it must first of all express the desire and need of the petitioner. We also need to move the heart of the person implored into granting the request. Now these two elements have no place in prayer made to God. When we pray, we do not have to worry about making our desires and needs plain to God who knows them all. In the words of the psalmist: "Lord, all my desire is before you." And we read in the gospel: "Your Father knows what you need."

There is no question either of moving the divine will, by the power of human words, into willing something other than the original divine purpose, for it is written in the Book of Numbers: "God is not a human that he should speak falsely, nor mortal, that he should change," and in the Book of Samuel: "He is not a human that he should repent."

Yet prayer is necessary to us in order to obtain grace from God; and this on account of the petitioner's own self, so that we can reflect on our own deficiencies and move our hearts to desire fervently and devotedly what we hope to obtain by prayer. This is how we make ourselves fit to receive.

There is another difference distinguishing prayer made to God from that addressed to people. Prayer addressed to a human being demands at the outset a certain degree of familiarity thanks to which the petitioner is sure of access to the one implored. However, prayer to God by itself makes us intimates of God, as our souls rise toward him, converse affectionately with him, and adore him in spirit and in truth.

This intimacy acquired through prayer encourages us to apply ourselves to prayer with confidence. For this cause it is written in the Psalm: "I call upon you" (that is, I pray confidently), "for you will answer me, O God." At the first prayer, the psalmist was received into the intimacy of God, and returns to pray thereafter with increased confidence. And so, in prayer to God, perseverance in or insistence on the request is not wearisome but indeed acceptable to God; as it is written in the gospel: 'You ought always to pray and not lose heart"; and elsewhere the Lord bids us: "Ask, and you will receive. Knock, and it will be opened to you."
Compendium of Theology 2. 1. Vives 5, 27: Lynch, 314-315