19 Q. Can God do all things? A. God can do all things, and nothing is hard or impossible to Him.
20 Q. Is God just, holy, and merciful? A. God is all just, all holy, all merciful, as He is infinitely perfect.
“All just”—that is, most just. “Just” means to give to everyone what belongs to him—to reward if it is merited or to punish if it is deserved. “Holy”—that is, good. “Merciful” means compassionate, forgiving, less exacting than severe justice demands. In a court a just judge is one who listens patiently to all the arguments for and against the prisoner, and then, comparing one with the other, gives the sentence exactly in accordance with the guilt. If he inflicts more or less punishment than the prisoner deserves, or for money or anything else gives an unfair sentence, then he is an unjust judge. The judge might be merciful in this way. The laws say that for the crime of which this prisoner is proved guilty he can be sent to prison for a term not longer than ten years and not shorter than five: that is, for anything between ten and five years. The judge could give him the full ten years that the law allows and be just. But suppose he believed that the prisoner did not know the law and did not intend to be as wicked as he was proved; or that it was his first offense, or that he heard the prisoner’s mother, who was old and infirm, pleading for him and saying he was her only support; or other extenuating circumstances that could awaken sympathy: the judge might be merciful and sentence him for the shortest term the law allows. But if the judge dismissed every prisoner, no matter how guilty, without punishment, he would not be a merciful but an unjust judge, who would soon be forced to leave the court. In the same way, God is often merciful to sinners and punishes them less than He could in strict justice. But if He were to allow every sinner to go without any punishment whatsoever—as unbelievers say He should do, by having no Hell for the wicked—then He would not be just. For as God is an Infinite Being, all His perfections must be infinite; that is, He must be as infinitely just as He is infinitely merciful, true, wise, or powerful.
Now He has promised to punish sin; and since He is infinitely true, He must keep His promise.
“Unity” means to be one, and “Trinity,” three in one.
21 Q. Is there but one God? A. Yes; there is but one God.
22 Q. Why can there be but one God? A. There can be but one God because God, being supreme and infinite, cannot have an equal.