First off, I want to say that if anyone has done what mman has suggested, then they are saved.
But, if anyone has done what JJump has said, they are also saved.
mman just adds a bunch of works to spiritual salvation that Scriptures do not support.
Now, onto Hebrews 5:9. Yes, they have the word "obey", and they all are referring to "them", but the key word - the word that different translations vary on - is the word "eternal".
In the Greek, it is the word for "age". Actually, it's an adjective, so it's "age-lasting" or "age-abiding".
The KJV translators, instead of going back to the Greek, went to the Latin Vulgate. The Latin Vulgate translated the Greek adjective "aionion" to the Latin "aeternus" in which we get the English word eternal and eternity.
This is why the word "eternal" has been misunderstood by the English reader. If the KJV translators would have gone to the Greek they for sure would have translated it as many translators such as Rotherham and Young, namely, age lasting or life for the age.
Most literal translations either translate the word as "age-lasting" (or something similar) or simply transliterate it.
"Eternal" means without beginning or ending, and there's a Greek word for it. ἀϊδίοις
"Everlasting" means without ending, and there's a Greek expression for it. εἰς τοὺς αἰῶνας τῶν αἰώνων
An age is a limited period of time. There's a Greek word for it. αἰωνίου
αἰωνίου is found in Hebrews 5:9. Different translations translate it differently:
CLV: Heb 5:9 And being perfected, He became the cause of eonian salvation to all who are obeying Him,
REV: Heb 5:9 And, being made perfect, became, to all them that obey him, Author of salvation age-abiding;
YLT: Heb 5:9 and having been made perfect, he did become to all those obeying him a cause of salvation age-during,
The theology of the West was not that of the Greek Church but that of Roman Catholicism. It was Latin theology. And just as it is beyond doubt that the revisers, translators, and lexicographers, were chiefly influenced by the Latin language and Latin translations, either directly or indirectly. It is admitted that the theology of Calvin was derived from Saint Augustine, modernized and extended.
S. S. Craig said, "“It was absolutely essential to Augustinian theology with its blightening emphasis on the doctrine of predestinarianism to mistranslate the Greek adjective aijw>niov, and put on it a meaning which the Greek will not for a moment allow in its respective applications to salvation and judgment.
And that was essential to Augustinian theology was equally essential to Latin Christianity from the days of Augustine to those of Calvin and Luther. And the same exists in the Reformed Theology from then till the present.
To say nothing of other words, the Calvinist simply cannot, dare not, face an honest and truthful interpretation of the two frequently occurring words with which we are now dealing with, namely “eternal life.” "
Because of this erroneous connection, even those who espouse areminianism are affected as well. If arminians were to apply their teachings to what the word actually means, then their viewpoint would be essentially correct, but since they apply it to spiritual salvation, they are in grave error.