A Matter of Justice
Why did God choose to save the human race, but not Lucifer and his angels?
This question seems to be based on the false assumption that God did not try to save Lucifer. Perhaps the intended question is Why did God not send His Son to save fallen angels? Although the cosmic conflict is a central topic in biblical theology, there is not a detailed exposition of its origin in the Bible, making it difficult to know everything God did on behalf of the heavenly host at the beginning of the conflict. All I can do is share some of my own thoughts as they relate to your question.
1. Justice and Love: Sin was not created; neither did it come into existence. It is in fact the denial of both creation and existence. It is the embracing of de-creation by intelligent creatures who chose the nothingness of nonexistence while claiming the irrational right to exist independent of God. There was no reason for a group of heavenly beings to rebel. Therefore, in condemning them God acted justly. But He was also acting lovingly by not allowing de-creation to totally overtake His good creation. The integrity of divine judgment against rebellious angels will even be recognized by them at the close of the cosmic conflict (e.g., Phil. 2:10, 11).
2. Uniqueness of Lucifer’s Sin: We usually understand sin as a condition (e.g., having a sinful nature) or as an act (e.g., violation of the law). In the case of Lucifer and his angels we are dealing with the strangest expression of sin and evil: they are not yet explicit; they are being gestated inside the angels, altering their nature in a radical way: decomposing it. This chaotic anomaly was slowly disintegrating a segment of God’s creation and expressed itself in rebellion against the will of the Creator. There is not yet an external power tempting creatures to sin. We are dealing with the moment sin and evil originated. This was not the condition of Adam and Eve. However, their sin was as inexcusable as that of Lucifer and deserved the same penalty.
3. Resolution and Revelation: God did all He could to save not only Lucifer and his angels but also the human race. The Bible suggests a constant dialogue with the rebellious angels in an attempt to persuade them that their course of action would damage the divine cosmic order and themselves. God tried to abort the origin of sin. Through His Son, the Mediator between God and His creation (Col. 1:15), God revealed to them His infinite love. Because they had been so close to God, they experienced in unique ways His love and care for all His creatures. They also realized that the Son of God who seemed to have been one more among them—the Archangel (Dan. 10:21; 12:1; Jude 9; 1 Thess. 4:16; Rev. 12:7)—was none other than their Creator (Col. 1:16). This magnificent revelation presumably caused many angels to return to their allegiance to God and should have brought the insurrection to an end, but that was not the case. A judicial process was set in place to examine the evidence and the arguments, but the decision of the tribunal was clear: “You were blameless in your ways from the day you were created till wickedness was found in you” (Eze. 28:15, NIV). Satan was found guilty. Once the self-corrupting nature of sin/evil de-created the goodness of the nature of Lucifer and his angels, there was absolutely nothing God could do to save them. They had rejected the divine revelation of God’s love for them.
God granted the same option to the human race. God’s most glorious revelation of His love for sinners through His Son, who became one of us through the incarnation, offers us the possibility or returning to our allegiance to God and living. Sin and evil have almost eradicated the image of God in us, but this process can come to an end if we see in Christ the most majestic revelation of His love that justly condemns rebellious creatures and justly saves repentant sinners (Rom. 3:25, 26).