The ancients suffered for their obedience to God. For example, the apostles “rejoic[ed] that they were counted worthy to suffer shame for his name” after being beaten and jailed (see Acts 5:41). Peter said “if any man suffer as a Christian, let him not be ashamed; but let him glorify God on this behalf.” (1 Peter 4:16) Why did they subject themselves to suffering? How did they find joy in doing so?
The answer is found in the principle of justice. Justice is the receipt of what is merited. God is just, in that everyone always eventually receives what they deserve (see Alma 41:15).
Justice requires two components. First, the recognition of what is merited. Second, the delivery of what is merited. Recognition of what is merited requires knowledge, without which reality can’t be perceived correctly and completely enough to establish an accurate accounting. Influence of outcomes requires power to arrange circumstances according to cause and effect.
One can only be as just as their knowledge of what is right, recognition of what is merited, and power to arrange outcomes allows. What good would it do for someone to recognize injustice if they have no ability to change outcomes, or to have power to arrange outcomes if they have a limited sense of what is right?
God is perfectly just. “He is the Rock, his work is perfect: for all his ways are judgment: a God of truth and without iniquity, just and right is he.” (Deuteronomy 32:4) God knows all things: “O how great the holiness of our God! For he knoweth all things, and there is not anything save he knows it.” (2 Nephi 9:20) God has all power: “...with God all things are possible.” (Matthew 19:26)
God’s justice is much more effectual than any other being’s justice could be because he has all knowledge, all power, and sees all things—meaning he is able to more accurately know what is right, recognize what is merited, and arrange outcomes according to what is merited.