"For God will bring every deed into judgment, including every hidden thing, whether it is good or evil." Ecclesiastes. 12:14
To understand the judgment of God, we need to follow the historical aspects of God and the judgments that He has done in the past. You see, there are two basic judgments with God. The present, physical judgment; and the "End of Time" eternal, spiritual judgment. Both work on the same principle: justice.
In the Bible we have many historical accounts of God in the present, physical judgment. Based on these present manifestations, we will be able to see the justice and the mercy of God in His end-time judgments. Let us begin in Genesis.
In Genesis chapter two, verse 17, we have God laying down the truth to Adam and Eve, saying, "If you eat of the tree of the knowledge of good and evil, you will "surely" die". That is the truth. That was the command. Their eternal life depended on one thing: obedience.