1 Jn 2:1-2 My little children, these things write I unto you, that ye sin not. And if any man sin, we have an advocate with the Father, Jesus Christ the righteous: 2 And he is the propitiation for our sins: and not for ours only, but also for the sins of the whole world. This means that He is the propitiation for our unbelief in addition to our other sins. That word propitiation also means reconciliation as in Heb 2:17 17 Wherefore in all things it behoved him to be made like unto his brethren, that he might be a merciful and faithful high priest in things pertaining to God, to make reconciliation for the sins of the people. Some other translations versions read: 17 Wherefore it behooved him in all things to be made like unto his brethren, that he might become a merciful and faithful high priest in things pertaining to God, to make propitiation for the sins of the people.ASV 17 So it is evident that it was essential that He be made like His brethren in every respect, in order that He might become a merciful (sympathetic) and faithful High Priest in the things related to God, to make atonement and propitiation for the people’s sins.AMP Now this propitiation, atonement, reconciliation occurred on the basis of His Death, and that even while believers were unbelievers and enemies Rom 5:10 10 For if, when we were enemies, we were reconciled to God by the death of his Son, much more, being reconciled, we shall be saved by his life. 10 If the death of his Son restored our relationship with God while we were still his enemies, we are even more certain that, because of this restored relationship, the life of his Son will save us. GW Understand something, for those of us Christ died for, because of His Death propitiating God on our behalf, while we were yet still enemies, we had been restored back in a right relation with, received into His Favour. The word reconciled in Rom 5:10 is the greek word katallassō: I.to change, exchange, as coins for others of equivalent value A.to reconcile (those who are at variance) B.return to favour with, be reconciled to one C.to receive one into favour And to be in the Favor of God is technically Salvation ! In His Favour is Life Ps 30:5 5 For his anger endureth but a moment; in his favour is life: weeping may endure for a night, but joy cometh in the morning. Prov 8:35 35 For whoso findeth me findeth life, and shall obtain favour of the Lord. Basically being in His Favor is also being accepted by Him ! Acts 10:35 35 But in every nation he that feareth him, and worketh righteousness, is accepted with him. Remember what God told cain ? Gen 4:7 7 If thou doest well, shalt thou not be accepted? and if thou doest not well, sin lieth at the door. And unto thee shall be his desire, and thou shalt rule over him. But this being accepted of Him and being in His Favor, is even while we are doing not well, being enemies and unbelievers Rom 5:10 ! Now why is this a fact even while we are enemies and unbelievers ? Its because Christ has done well for us, and is being the propitiation for our sins, not to exclude the sin of unbelief, disobedience ! See if unbelief was not propitiated for, it would not have been possible for us to be reconciled to God while still being enemies and unbelievers, which Rom 5:10 testifies to. To say that the sin of unbelief was not propitiated for, overthrows and denies the very blessed Truth of propitiation altogether, which in essence is to deny the death / blood of Jesus Christ !