John 17:14-23
14 I have given them Your word; and the world has hated them because they are not of the world, just as I am not of the world.
15 I do not pray that You should take them out of the world, but that You should keep them from the evil one.
16 They are not of the world, just as I am not of the world.
17 Sanctify them by Your truth. Your word is truth.
18 As You sent Me into the world, I also have sent them into the world.
19 And for their sakes I sanctify Myself, that they also may be sanctified by the truth.
Jesus Prays for All Believers
20 "I do not pray for these alone, but also for those who will believe in Me through their word;
21 that they all may be one, as You, Father, are in Me, and I in You; that they also may be one in Us, that the world may believe that You sent Me.
22 And the glory which You gave Me I have given them, that they may be one just as We are one:
23 I in them, and You in Me; that they may be made perfect in one, and that the world may know that You have sent Me, and have loved them as You have loved Me.
NKJV
If a person does not believe that Jesus' shed blood on the cross saves them then they are not saved. Believing in Jesus' shed blood on the cross is the only way it applies to a person.
1 Cor 15:1-11
15 Moreover, brethren, I declare to you the gospel which I preached to you, which also you received and in which you stand,
2 by which also you are saved, if you hold fast that word which I preached to you — unless you believed in vain.
3 For I delivered to you first of all that which I also received: that Christ died for our sins according to the Scriptures,
4 and that He was buried, and that He rose again the third day according to the Scriptures,
5 and that He was seen by Cephas, then by the twelve.
6 After that He was seen by over five hundred brethren at once, of whom the greater part remain to the present, but some have fallen asleep.
7 After that He was seen by James, then by all the apostles.
8 Then last of all He was seen by me also, as by one born out of due time.
9 For I am the least of the apostles, who am not worthy to be called an apostle, because I persecuted the church of God.
10 But by the grace of God I am what I am, and His grace toward me was not in vain; but I labored more abundantly than they all, yet not I, but the grace of God which was with me.
11 Therefore, whether it was I or they, so we preach and so you believed.
NKJV
believing = Faith = trust = confidence. These words all mean this same thing. Believing the gospel of grace is the only thing that saves in this age of grace. There was a time when the Law of Moses was given to the Jews. Today there is a gospel of God's grace given to Paul for all of mankind. You can't mix law with grace. Law equals what man earns. Grace equals a free gift.
Today there is only one way to Heaven and that is through the sin offering made by Jesus' blood on the cross. All those that place their belief, faith, trust and confidence in what Jesus did are saved.