The Catechism sections for today deal with the knowledge of God and how we can Speak of Him. Again, Aquinas makes a major contribution for us, which I have included below. Isn’t it great to learn about the faith?

III. The Knowledge of God According to the Church

36 "Our holy mother, the Church, holds and teaches that God, the first principle and last end of all things, can be known with certainty from the created world by the natural light of human reason."11 Without this capacity, man would not be able to welcome God's revelation. Man has this capacity because he is created "in the image of God".12

37 In the historical conditions in which he finds himself, however, man experiences many difficulties in coming to know God by the light of reason alone:
Though human reason is, strictly speaking, truly capable by its own natural power and light of attaining to a true and certain knowledge of the one personal God, who watches over and controls the world by his providence, and of the natural law written in our hearts by the Creator; yet there are many obstacles which prevent reason from the effective and fruitful use of this inborn faculty. For the truths that concern the relations between God and man wholly transcend the visible order of things, and, if they are translated into human action and influence it, they call for self-surrender and abnegation. the human mind, in its turn, is hampered in the attaining of such truths, not only by the impact of the senses and the imagination, but also by disordered appetites which are the consequences of original sin. So it happens that men in such matters easily persuade themselves that what they would not like to be true is false or at least doubtful.13

38 This is why man stands in need of being enlightened by God's revelation, not only about those things that exceed his understanding, but also "about those religious and moral truths which of themselves are not beyond the grasp of human reason, so that even in the present condition of the human race, they can be known by all men with ease, with firm certainty and with no admixture of error".14

IV. How Can We Speak about God?

39 In defending the ability of human reason to know God, the Church is expressing her confidence in the possibility of speaking about him to all men and with all men, and therefore of dialogue with other religions, with philosophy and science, as well as with unbelievers and atheists.

40 Since our knowledge of God is limited, our language about him is equally so. We can name God only by taking creatures as our starting point, and in accordance with our limited human ways of knowing and thinking.

41 All creatures bear a certain resemblance to God, most especially man, created in the image and likeness of God. the manifold perfections of creatures - their truth, their goodness, their beauty all reflect the infinite perfection of God. Consequently we can name God by taking his creatures" perfections as our starting point, "for from the greatness and beauty of created things comes a corresponding perception of their Creator".15

42 God transcends all creatures. We must therefore continually purify our language of everything in it that is limited, imagebound or imperfect, if we are not to confuse our image of God --"the inexpressible, the incomprehensible, the invisible, the ungraspable"-- with our human representations.16 Our human words always fall short of the mystery of God.

43 Admittedly, in speaking about God like this, our language is using human modes of expression; nevertheless it really does attain to God himself, though unable to express him in his infinite simplicity. Likewise, we must recall that "between Creator and creature no similitude can be expressed without implying an even greater dissimilitude";17 and that "concerning God, we cannot grasp what he is, but only what he is not, and how other beings stand in relation to him."18

IN BRIEF

47 The Church teaches that the one true God, our Creator and Lord, can be known with certainty from his works, by the natural light of human reason (cf. Vatican Council I, can. 2 # 1: DS 3026),

48 We really can name God, starting from the manifold perfections of his creatures, which are likenesses of the infinitely perfect God, even if our limited language cannot exhaust the mystery.

49 Without the Creator, the creature vanishes (GS 36). This is the reason why believers know that the love of Christ urges them to bring the light of the living God to those who do not know him or who reject him.

John Paul II wrote about the need to be enlightened by God’s revelation in Catechesi Tradendae:

14. To begin with, it is clear that the Church has always looked on catechesis as a sacred duty and an inalienable right. On the one hand, it is certainly a duty springing from a command given by the Lord and resting above all on those who in the new covenant receive the call to the ministry of being pastors. On the other hand, one can likewise speak of a right: from the theological point of view every baptized person, precisely the reason of being baptized, has the right to receive from the Church instruction and education enabling him or her to enter on a truly Christian life; and from the viewpoint of human rights, every human being has the right to seek religious truth and adhere to it freely, that is to say, "without coercion on the part of individuals or of social groups and any human power," in such a way that in this matter of religion, "no one is to be forced to act against his or her conscience or prevented from acting in conformity to it."

Here is the full text of Aquinas’ Summa Contra Gentiles, Chapter 30, which deals with how we can speak of God:

Chapter 30

The Names That Can Be Predicated Of God

1. From what we have said we can further consider what it is possible to say or not to say of God, what is said of Him alone, and also what is said of Him and other things together.

2. Since it is possible to find in God every perfection of creatures, but in another and more eminent way, whatever names unqualifiedly designate a perfection without defect are predicated of God and of other things: for example, goodness, wisdom, being, and the like. But when any name expresses such perfections along with a mode that is proper to a creature, it can be said of God only according to likeness and metaphor. According to metaphor, what belongs to one thing is transferred to another, as when we say that a man is a stone because of the hardness of his intellect. Such names are used to designate the species of a created thing, for example, man and stone, for to each species belongs its own mode of perfection and being. The same is true of whatever names designate the properties of things, which are caused by the proper principles of their species. Hence, they can be said of God only metaphorically. But the names that express such perfections along with the mode of supereminence with which they belong to God are said of God alone. Such names are the highest good, the first being, and the like.

3. I have said that some of the aforementioned names signify a perfection without defect. This is true with reference to that which the name was imposed to signify; for as to the mode of signification, every name is defective. For by means of a name we express things in the way in which the intellect conceives them. For our intellect, taking the origin of its knowledge from the senses, does not transcend the mode which is found in sensible things, in which the form and the subject of the form are not identical owing to the composition of form and matter. Now, a simple form is indeed found among such things, but one that is imperfect because it is not subsisting; on the other hand, though a subsisting subject of a form is found among sensible things, it is not simple but rather concreted. Whatever our intellect signifies as subsisting, therefore, it signifies in concretion; but what it signifies as simple, it signifies, not as that which is, but as that by which something is. As a result, with reference to the mode of signification there is in every name that we use an imperfection, which does not befit God, even though the thing signified in some eminent way does befit God. This is clear in the name goodness and good. For goodness has signification as something not subsisting, while good has signification as something concreted. And so with reference to the mode of signification no name is fittingly applied to God; this is done only with reference to that which the name has been imposed to signify. Such names, therefore, as Dionysius teaches [De divinis nominibus I, 5, De caelesti hierarchia II, 3], can be both affirmed and denied of God. They can be affirmed because of the meaning of the name; they can be denied because of the mode of signification.

4. Now, the mode of supereminence in which the abovementioned perfections are found in God can be signified by names used by us only through negation, as when we say that God is eternal or infinite, or also through a relation of God to other things, as when He is called the first cause or the highest good. For we cannot grasp what God is, but only what He is not and how other things are related to Him, as is clear from what we said above.

Footnotes
11 Vatican Council I, Dei Filius 2: DS 3004 cf. 3026; Vatican Council II, Dei Verbum 6.
12 Cf. ⇒ Gen 1:27
13 Pius XII, Humani generis 561: DS 3875.
14 Pius XII, Humani generis 561: DS 3876; cf. Dei Filius 2: DS 3005; DV 6; St. Thomas Aquinas, S Th I, I, I.
15 ⇒ Wis 13:5
16 Liturgy of St. John Chrysostom, Anaphora.
17 Lateran Council IV: DS 806.
18 St. Thomas Aquinas, SCG 1, 30.