All sinners Christ died for become believers because they are His Spiritual offspring. Isa 53:10
10 Yet it pleased the Lord to bruise him; he hath put him to grief: when thou shalt 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.
This scripture is about the Lord Jesus Christ, and the phrase "when thou shalt make his soul an offering for sin" Speaks of His Death, being made sin [ a sin offering 2 Cor 5:21] and the second phrase " he shall see his seed", speaks of his spiritual offspring as a result of his soul for them, being made an offering for sin.
Now Jesus speaks of this same blessed truth in Jn 12:24
24 Verily, verily, I say unto you, Except a corn of wheat fall into the ground and die, it abideth alone: but if it die, it bringeth forth much fruit.
Christ here is the corn of wheat that will fall into the ground and die [speaking of his soul being made a offering for sin] and if he die, the result is [his dying] bringeth forth fruit, which equates to he shall see his seed. Now the word seed in Isa 53:10 is the word zera and means:
offspring, descendants, posterity, children and it also means : fruit
Now the word fruit is Jn 12:24 is the grk word karpos and means:
the fruit of one's loins, i.e. his progeny, his posterity
And Jn 12:24 gives a definite statement as to what will occur if the corn of wheat die, it bringeth forth or produce much fruit.
So a spiritual seed for Christ is promised as a result, effect of His dying !