We are Justified, made right with God, if and when Christ has taken away our sins, Jn 1:29
29 The next day John seeth Jesus coming unto him, and saith, Behold the Lamb of God, which taketh away the sin of the world.
1 Jn 3:5
And ye know that he was manifested to take away our sins; and in him is no sin.
Heb 10:11-12
11 And every priest standeth daily ministering and offering oftentimes the same sacrifices, which can never take away sins:
12 But this man, after he had offered one sacrifice for sins for ever, sat down on the right hand of God;
The implication here is this man did what other priest could not do, take away sins !
But the Man/Priest Christ did this, not our believing it, so we are Justified and had our sins taken away before we believed !