The definition of just is, “acting or being in conformity with what is morally upright or good.” Who defines what is morally upright or good? If we use our own definition of morally upright and good, then it changes every few years. What was thought to be morally upright 100 years ago has radically changed in this country and many others as well. Though to be fair, 100 years ago, people still practiced immoral activity, but they didn’t try to sell it to us as moral. They knew it was wrong, but just went ahead and did it anyway.
If God were unjust it would mean that he not only does morally wrong things, but he would also change the definition of what is morally right and wrong just like we do. However, when you read the Bible, the things that are described as immoral do not change from the beginning to the end. God doesn’t change so his standard of what is right and wrong doesn’t change. Regarding his character, the Bible says, “He is the Rock, his works are perfect, and all his ways are just. A faithful God who does no wrong, upright and just is he” (Deut 32:4). God has set the standard for moral uprightness and he is the only one who can meet that standard.
None of us can live a life without breaking at least one of God’s moral standards. Who has never told a lie? Who has never thought badly about another person? (Should you object to these being God’s standards, remember that these are universally accepted as wrong in every society.) Who has ever always done the right thing, at the right time, every time? Jesus is the only one who has ever met that standard and that is why he is qualified to die in our place.