Okay then, thats what Justified them before God, His death for them. Simple. Rom 5:9
9 Much more then, being now justified by his blood, we shall be saved from wrath through him.
Thats the object of Faith, Ones Justification by the Blood of Christ.
Isa 53:11
11 He shall see of the travail of his soul, and shall be satisfied: by his knowledge shall my righteous servant justify many; for he shall bear their iniquities.
By you saying Christs death isnt Justification before God, to me is unbelief to what Christs death actually accomplished, just being honest with you friend