Why does God choose to give grace to some individuals but not to all?

The concept of grace in Christianity is often understood as an unmerited gift or favor from God. According to Christian beliefs, God's decision to give grace to some individuals but not to all is based on his divine will and plan, which may not be fully understood by humans. This idea is rooted in the belief that God's ways are higher than human ways, and that his choices are ultimately just and righteous, even if they may seem mysterious or unfair to us.