Humanity needs a Savior. To give an exhaustive answer to why we need a Savior would require encyclopedic volumes of information. In our limited space, we will present some ideas, based on what the Bible says, about why we need a Savior.
First, let us understand the term we in this question to be technically inclusive; that is, when we say, “we need a Savior,” we mean that every person who has ever lived needs a Savior. Also, we should note that the term savior enjoys a somewhat broad use in the Bible; anyone who performs an act of rescue or deliverance may be designated as a “savior”—examples include the judges Othniel and Ehud (Judges 3:9, 15). God Himself (and not just Jesus specifically) is also called “Savior” (Isaiah 43:11; 45:21–22; 60:16). In this article, to avoid confusion, we will use the word Savior to designate Jesus Christ.
The reason we need a Savior has its roots in the nature of God and the nature of man: first, the Bible says God has a plan and human beings are critical to that plan. Second, God is holy, and He cannot abide in sin. Third, every human being has sinned, and every human has an intrinsic sin nature.
The difficulty for us is that living with God requires sinless perfection, and none of us is perfect. So God cannot accomplish His goals without first fixing humankind. That is why we need a Savior—and Scripture identifies Him as Jesus Christ (Luke 2:11; Titus 2:13–14).
We need the Savior, Jesus, because we need to be made holy: “without holiness no one will see the Lord” (Hebrews 12:14). Jesus does not simply make us better people; nor does He boost our godliness or augment our holiness—we have none to begin with. Rather, He makes us completely new creatures (2 Corinthians 5:17; Galatians 6:15).
The plan of God for humankind. We need a Savior because God plans for us to bring Him glory (Isaiah 43:7) and enjoy His fellowship forever (Psalm 27:4). He desires to conform us to the image of His Son (Romans 8:29).
The Self-Existent One did not create the cosmos to entertain Himself. He did so to cultivate relationships with beings made in His image (see Genesis 1:27). God (as a social and moral agent) desires to have His creation love Him and thrive. The fact that we (as volitional beings) fell into sin and rebellion means that we need a Savior, or God’s plan for us cannot be realized. In His love, God sent the Savior—His only begotten Son—so He could fit us for eternity and showcase His glory.
The holiness of God. With over 900 biblical references to the holiness of God, its importance to His creation cannot be overstated. The Bible teaches that we should pursue holiness (1 Peter 1:15).
Jesus taught that we should approach God with the understanding that He is holy (Matthew 6:9). We need a Savior because God is too pure to abide sinfulness: “Your eyes are too pure to look on evil; you cannot tolerate wrongdoing” (Habakkuk 1:13). Without a Savior, God’s word to us would only be “away from me, you evildoers!” (Matthew 7:23).
The sinfulness of humankind. In Romans 3:10–18 Paul brings passages from Psalms and Isaiah into a discussion of the law. In so doing he uses Scripture to conclude with confidence that every person has sinned (Romans 3:23). Every person therefore requires remediation. We cannot cast off our sin any more than a leopard can change its spots (Jeremiah 13:23). “There is no one righteous, not even one” (Romans 3:10; cf. Psalm 14:1).
God says in no uncertain terms that everyone is a sinner, even the ones who don’t think they are (see 1 John 1:8). What this means is that everyone needs a Savior, even the ones who don’t think they do.
The necessity of a Savior. To summarize, God has a plan. It is perfect, and He won’t change His mind about executing it. His plan involves us humans, though, and we are sinners through and through. Since God is holy, He cannot tolerate the presence of sin, and, unless He somehow cleanses us, it is impossible for Him to work His eternal plan with us. Those who are not cleansed—those who are not saved—must be separated from God for all eternity. God’s solution: offer the perfect sacrifice, once and for all, to cleanse us of sin and reconcile us to Himself. This He did with His Son on the cross.
We need a Savior because we cannot save ourselves. We need a Savior because, without Christ, we are described as “having no hope and without God in the world” (Ephesians 2:12, ESV).
We need a Savior, and God has provided one. Jesus saved us as a demonstration of God’s love and as a function of His mercy. Now, “having been justified by his grace, we . . . become heirs having the hope of eternal life” (Titus 3:7). Jesus’ sacrifice unlocked everything for us—and if there were any other way for God to work His plan without compromise, He would have chosen that over the humiliation of the cross (see Luke 22:42). The fact that Jesus did indeed die on the cross is proof enough that we need a Savior.