Nearly a couple thousand years ago, God Who had put on human nature, died for our sins on the Cross of Calvary. He rose from the dead too, shortly afterward, to prove that His Sacrifice for us was accepted by God the Father. This is what we all need to believe in order to be saved from the just punishment of all our misdeeds.
16 For God so loved the world that he gave his one and only Son, that whoever believes in him shall not perish but have eternal life.
John 3:16 (NIV)
This was necessary because all of us human beings are born in sin. That is, we all possess a sin nature that causes us to desire to disobey God by nature. Right from our first breath, even when we are ignorant of authority and of God, by nature we run toward evil and mischief. Regardless how others perceive us or what we think of our own selves, we possess evil in our hearts and act on it at every turn.
8 If we say that we have no sin, we deceive ourselves, and the truth is not in us.
1 John 1:8 (NKJV)
23 for all have sinned and fall short of the glory of God
Romans 3:23 (NKJV)
12 . . . through one man sin entered the world, and death through sin, and thus death spread to all men, because all sinned—
Romans 5:12 (NKJV)
19 For as by one man’s disobedience many were made sinners, so also by one Man’s obedience many will be made righteous.
Romans 5:19 (NKJV)
18 For I know that in me (that is, in my flesh) nothing good dwells; for to will is present with me, but how to perform what is good I do not find.
Romans 7:18 (NKJV)
This is the Bible’s position on this. We are all sinners. It may be argued, as it sometimes is, that ignorance makes us innocent, but obviously, the Bible does not hold this view. When Eve sinned, she did so ignorantly. The Bible says that she was deceived (1 Timothy 2:14; Genesis 3:13). Yet, we do not see that the Lord held her guiltless because of her ignorance (Genesis 3:16). Likewise, the Lord does not spare the ignorant just because they are ignorant.
47 And that servant who knew his master’s will, and did not prepare himself or do according to his will, shall be beaten with many stripes. 48 But he who did not know, yet committed things deserving of stripes, shall be beaten with few. For everyone to whom much is given, from him much will be required; and to whom much has been committed, of him they will ask the more.
Luke 12:47-48 (NKJV)
So, not knowing that we are sinners, not knowing that we are committing sin with some thought, word, or deed, does not spare us of the judgment due to sin. The Lord will still punish us for sinning. We all sin, whether we know that we do or we don’t.
In order to spare us the due consequence of our sin, however, the Lord in great mercy gave His Son, the Only One of His Kind, to die spiritually for us on the Cross of Calvary, so that we can be spared.
17 And He, bearing His cross, went out to a place called the Place of a Skull, which is called in Hebrew, Golgotha, 18 where they crucified Him, and two others with Him, one on either side, and Jesus in the center . . . 30 So when Jesus had received the sour wine, He said, “It is finished!” And bowing His head, He gave up His spirit.
John 19:17-18,30 (NKJV)
4 Surely He has borne our griefs
And carried our sorrows;
Yet we esteemed Him stricken,
Smitten by God, and afflicted.
5 But He was wounded for our transgressions,
He was bruised for our iniquities;
The chastisement for our peace was upon Him,
And by His stripes we are healed.
6 All we like sheep have gone astray;
We have turned, every one, to his own way;
And the LORD has laid on Him the iniquity of us all.
7 He was oppressed and He was afflicted,
Yet He opened not His mouth;
He was led as a lamb to the slaughter,
And as a sheep before its shearers is silent,
So He opened not His mouth.
8 He was taken from prison and from judgment,
And who will declare His generation?
For He was cut off from the land of the living;
For the transgressions of My people He was stricken.
9 And they made His grave with the wicked—
But with the rich at His death,
Because He had done no violence,
Nor was any deceit in His mouth.
10 Yet it pleased the LORD to bruise Him;
He has put Him to grief.
When You make His soul an offering for sin,
He shall see His seed, He shall prolong His days,
And the pleasure of the LORD shall prosper in His hand.
11 He shall see the labor of His soul, and be satisfied.
By His knowledge My righteous Servant shall justify many,
For He shall bear their iniquities.
12 Therefore I will divide Him a portion with the great,
And He shall divide the spoil with the strong,
Because He poured out His soul unto death,
And He was numbered with the transgressors,
And He bore the sin of many,
And made intercession for the transgressors.
Isaiah 53:4-12 (NKJV)
No human being now has to suffer the just consequence of our many sins. There is no need at all for anyone to have any fear concerning our fate with God. Since the Lord Jesus’s Sacrifice was accepted by the Father, nothing more needs to be done for us to be saved. Our sins have all been completely paid for.
We must believe that this is true, however, in order to be able to take advantage of it. It is not possible to escape eternal condemnation unless we believe that Jesus Christ, this Man who is also God, has died for our sins and been raised from the dead too because God accepted His Sacrifice. Without accepting this as true, we simply cannot be saved, any more than we can be saved from drowning if we don’t grab the lifeline that is offered to us.
12 But as many as received Him, to them He gave the right to become children of God, to those who believe in His name
John 1:12 (NKJV)
14 And as Moses lifted up the serpent in the wilderness, even so must the Son of Man be lifted up, 15 that whoever believes in Him should not perish but have eternal life. 16 For God so loved the world that He gave His only begotten Son, that whoever believes in Him should not perish but have everlasting life. 17 For God did not send His Son into the world to condemn the world, but that the world through Him might be saved. 18 “He who believes in Him is not condemned; but he who does not believe is condemned already, because he has not believed in the name of the only begotten Son of God.
John 3:14-18 (NKJV)
There is no need for any further action to be carried out in order for anyone to be saved. In fact, it would be blasphemy to add anything to the Cross of Jesus Christ for one to be saved, whether that thing is water baptism, some code of conduct, identification with one organization or another, or any other thing. Salvation is purely a gift of God that we can only receive by believing in Jesus Christ (cf. Galatians 5:4).
8 For by grace you have been saved through faith, and that not of yourselves; it is the gift of God, 9 not of works, lest anyone should boast.
Ephesians 2:8-9 (NKJV)