The fourth question of the Westminster Shorter Catechism asks, "What is God?" It answers, "God is a Spirit, infinite, eternal, and unchangeable in his being, wisdom, power, holiness, justice, goodness, and truth."
God has revealed himself to man, so that we are not in the dark about his existence or nature. Our knowledge of him, when based upon his revelation of himself, is limited but true. He has revealed himself in his creation (Rom. 1:19-20) and in the Holy Scriptures.
What does it mean that God is a Spirit? God reveals that he is a Spirit (John 4:24). This means that the divine nature is not physical. God as God has no body. As our confession of faith says, he is "a most pure spirit, invisible, without body, parts, or passions." When Jesus rose from the dead, he contrasted spirit with body: "Touch me, and see. For a spirit does not have flesh and bones as you see that I have" (Luke 24:39). Jesus only had a body because he took on human nature.
What about references to God’s hand, God’s arm, God’s eyes, God’s face? These are figures of speech that use human body parts to refer to God’s invisible attributes (e.g. his power, knowledge, favor, etc.). He sees, he hears, he acts, he speaks, but without physical eyes, ears, hands, or mouth. He does not need the organs for these activities.
What does it mean for God to be infinite? He is without limit. He is not bound or measured. He is everywhere, filling heaven and earth, and even they cannot contain him (Jer. 23:24, 1 Kings 8:27).
What does it mean for God to be eternal? He is not limited by time, but is beyond time. He existed before time began. He has no beginning and no end. "Before the mountains were brought forth, or ever you had formed the earth and the world, from everlasting to everlasting you are God. You return man to dust and say, 'Return, O children of man!' For a thousand years in your sight are but as yesterday when it is past, or as a watch in the night" (Psalm 90:2–4).
What does it mean for God to be unchangeable? He is perfect and therefore cannot grow better or get worse. He is infinite and eternal, not a creature of time. He does not vary or change (James 1:17). “They will perish, but you will remain; they will all wear out like a garment. You will change them like a robe, and they will pass away, but you are the same, and your years have no end. The children of your servants shall dwell secure; their offspring shall be established before you” (Psalm 102:26-28).
How is God’s being different from our being? It is infinite, eternal, and unchangeable. God is infinite, eternal, and unchangeable, and these attributes apply to his being, wisdom, power, holiness, justice, goodness, and truth. That is, his being is infinite, eternal, and unchangeable. His wisdom is infinite, eternal, and unchangeable. His power is infinite, eternal, and unchangeable. And so forth.
What is God’s wisdom?It is his perfect knowledge of himself and all things by which he orders and connects all things with purpose and design and ultimately for his glory. His wisdom is displayed in the design and order of the creation and his providence (Psalm 104), in his law (Deut. 4:6), and in his work of salvation through Jesus Christ, the wisdom of God (1 Cor. 1-2).
What is God’s power? It is his ability to do whatever he pleases (Ps. 135:6-7). He has supreme authority over all things and he has infinite power. He works all things according to the counsel of his will (Eph. 1:10; note the union of wisdom and power). His power is displayed in creating all things out of nothing by his word (Rev. 4:11), by sustaining all things by his word (Heb. 1), by working all things to fulfill his purposes (Dan. 4:35), and by overcoming sin and Satan through the miraculous incarnation and work of Jesus Christ (1 Cor. 1:24).
What is God’s holiness? Holiness has to do with separation, consecration, and purity. Thomas Vincent describes it this way: “The holiness of God is his essential property, whereby he is infinitely pure; loves and delights in his own purity, and in all the resemblances of it which any of his creatures have; and is perfectly free from all impurity, and hates it where he sees it.” Consider Isaiah 6:3, Revelation 4:8, and 1 Peter 1:15-16.
What is God’s justice? God is perfectly just and right in himself and in his dealing with others, rendering to everyone his due. He is just in the laws he gives, in his actions toward his creatures, and in his judgments as the Judge of the earth. As Abraham said, “Shall not the Judge of all the earth do what is just?” (Gen. 18:25). He will by no means clear the guilty (Ex. 34:7). As Deuteronomy 32:4 says, “The Rock, his work is perfect, for all his ways are justice. A God of faithfulness and without iniquity, just and upright is he.” He displays his justice in the sacrifice of Christ to satisfy divine justice, in his temporal judgments in history, and in the final judgment on the last day. His justice is a good thing, for which creation longs (Ps. 96, 98), and to which we appeal as those in Christ (1 John 1:9, Gen. 18:25, Luke 18:1-8).
What is God’s goodness? It is that whereby he is goodness himself, is generous and kind, and is the author of all good. Consider how man was made. Before man did anything, God supplied him with a world of good things, full of beauty, usefulness, and delight, and gave him dominion over it. Even now, God is generous to all and patient toward the rebellious. “For he makes his sun rise on the evil and on the good, and sends rain on the just and on the unjust” (Matthew 5:45). His kindness is meant to lead men to repentance. His goodness is especially shown in his work of love and grace in the salvation of sinners through Christ. By grace, he brings us back to an enjoyment of himself, the true good, and the right use of all his good gifts. To the redeemed, the creation is their Father’s world. Truly, as Psalm 145:8–9 says, “The LORD is gracious and merciful, slow to anger and abounding in steadfast love. The LORD is good to all, and his mercy is over all that he has made.”
What is God’s truth? God is faithful and true and speaks the truth, not falsehood. “…in hope of eternal life, which God, who never lies, promised before the ages began…” (Titus 1:2). The devil is a liar and the father of lies who deceived Eve. But God cannot be mistaken and he cannot be unfaithful. He is faithful, so that what he says is true and what he has said he will do he will perform - he is true to his word. He abounds in steadfast love and faithfulness (Ex. 34:6).
God is not limited by time or space. Neither is God foolish, weak, common, unjust, miserly, or fickle. Our experience can at times provoke us to feel that God is weak, unjust, miserly, etc. But we must hold fast to his word and believe that God is who he says he is in the midst of trials. Remember what he has done for you. Remember what you have received from him. Remember what he has done for his people in the past. Remember what he has done in your life, taking pity on you when you were doomed to death.