The Creator is a fair Judge; One who judges each man according to his particular circumstances

The Creator is a fair Judge; One who judges each man according to his particular circumstances

When it comes to the Almighty [blessed be He], “Right” & “Wrong” are relative terms, as the Creator's judgment is " results oriented". In other words, what matters to Him isn't the accuracy of our theology, but rather the goodness [or evil] we do with whatever truth we happen to have in our hands.
Consider the case of the Holy Ark- The Philistines took it [in war] and impudently placed it inside the temple of their pagan god (“When the Philistines took the ark of God, they brought it into the house of Dagon, and set it by Dagon”- 1 Samuel 5: 2). Then they moved it around unto another citi (1 Samuel 5: 10). Finally, they put it upon an ox driven cart, and sent it back to Israel (“And the men did so; and took two milch kine, and tied them to the cart, and shut up their calves at home: And they laid the ark of the Lord upon the cart, and the coffer with the mice of gold and the images of their emerods”- 1 Samuel 6: 10-11, KJV). During this whole process, the Philistines touched the Ark, they pushed it around, and even opened it.
Yet, though they touched the Ark [and looked inside of it], we don't see God killing [right away] any Philistine, as they had no knowledge concerning how to handle God's holy things. On the other hand, Scripture tells us that, as soon as the Ark returned to Israel, the Hebrew dwellers of Bethshemesh looked inside of it, and they were immediately stricken by God. As is written: “And He [God] smote the men of Bethshemesh, because they had looked into the ark of the Lord, even he smote of the people fifty thousand and threescore and ten men: and the people lamented, because the Lord had smitten many of the people with a great slaughter”- 1 Samuel 16: 19, KJV.
Not only that, but Scripture records another case where a Hebrew man named Uzzah dared to touch the Ark, and was immediately struck down by God: “And when they came to Nachon's threshingfloor, Uzzah put forth his hand to the ark of God, and took hold of it; for the oxen shook it. And the anger of the Lord was kindled against Uzzah; and God smote him there for his error; and there he died by the ark of God”- 2 Samuel 6: 6-7, KJV.
In short, the Holy One is lenient with the Gentile, who doesn't know exactly what God expects from Him; but He is stern with the Hebrew believer, who has extensive knowledge of Torah. And this also agrees with the Christian Gospel, when it goes on to say: “And that servant, which knew his lord's will, and prepared not himself, neither did according to his will, shall be beaten with many stripes. But he that knew not, and did commit things worthy of stripes, shall be beaten with few stripes. For unto whomsoever much is given, of him shall be much required: and to whom men have committed much, of him they will ask the more”- Luke 12: 47-48, KJV

Will Hebrew believers “get lost” for refusing to believe Jesus to be God in the flesh?

When it comes to our everlasting destiny, it wouldn’t be wise to risk it by taking unnecessary chances. Granted-- there's a remote possibility of Jesus (peace and blessings be upon him) being a manifestation of God in the flesh, but the fact is that [unlike the God who spoke to Moses] Jesus didn't personally write anything; So, all we have from him is private/third-party “hear say”.
On the other hand, Moses actually wrote his five books of Torah, and they contained the words of the public revelation made by God to over 2 million Israelites.
In fact, Moses writings not only referenced God's personal writing (the Ten Commandments, written by God himself upon the two stone tablets) but also claim to be complete, not needing any future addition and/or modification (“And it came to pass, when Moses had made an end of writing the words of this law in a book, until they were finished, That Moses commanded the Levites... Ye shall not add unto the word which I command you, neither shall ye diminish ought from it... ”- Deuteronomy 31: 24-25, & Deuteronomy 4: 2, KJV).
And since the gospel writers freely acknowledge the fact that God not only spoke personally spoke to Moses (“.. have ye not read in the book of Moses, how in the bush God spake unto him, saying, I am the God of Abraham, and the God of Isaac, and the God of Jacob? ”- Mark 12: 26, KJV), but also that Moses himself wrote his books of Torah (“For had ye believed Moses, ye would have believed me; for he wrote of me”- John 5: 46, KJV), It is safe to stick to Moses public revelation [which is by the way the very definition of being a Samaritan believer].
But what if we are wrong, and Jesus is indeed God in the flesh? Will that make us lose our good share in the World to come? of course not! Why? Because the God of the Hebrews is perfectly righteous (“He is the Rock, his work is perfect: for all his ways are judgment: a God of truth and without iniquity, just and right is He”- Deuteronony 32: 4, KJV), and therefore never behaves like a religious tyrant, nor as an ideological dictator.
And even the Jewish Scripture bears witness of this, when it goes on to relate the story of God rewarding a whole family (The House of the Rechabites). For what reason were they rewarded? For their act of disbelief/disobedience to the words of a prophet (Jeremiah)!.
And why would God reward them for refusing to believe and/or obey the words of His anointed messenger? Simply because their disobedience was the result of an honest and sincere belief that man ought to stand firm by the words of fidelity exchanged between him and his father (which by the way is also intimated in the verse that goes on to say, “Lord, who shall abide in thy tabernacle? who shall dwell in thy holy hill?... He that sweareth to his own hurt, and changeth not... ”- Psalm 15: 1& 4, KJV).
As is written: “And I [Jeremiah] set before the sons of the house of the Rechabites pots full of wine, and cups, and I said unto them, Drink ye wine. But they said, We will drink no wine: for Jonadab the son of Rechab our father commanded us, saying, Ye shall drink no wine, neither ye, nor your sons for ever... Thus have we obeyed the voice of Jonadab the son of Rechab our father in all that he hath charged us... And Jeremiah said unto the house of the Rechabites, Thus saith the Lord of hosts, the God of Israel; Because ye have obeyed the commandment of Jonadab your father, and kept all his precepts, and done according unto all that he hath commanded you: Therefore thus saith the Lord of hosts, the God of Israel; Jonadab the son of Rechab shall not want a man to stand before me for ever”- Jeremiah 35: 5-8, & 18-19, KJV.
And it goes without saying that, if God was so pleased with the Children of Rechab for holding fast to the promise of fidelity made by their fathers to Jonadab, how much more will He be pleased with the Children of Israel for holding fast to the promise of fidelity [to God's Law] made by their fathers to “Jehovah”; a promise to be God’s people, and for Him to be their only God.
As is written: “Thou hast avouched the Lord (YHVH) this day to be thy God, and to walk in his ways, and to keep his statutes, and his commandments, and his judgments, and to hearken unto his voice: And the Lord hath avouched thee this day to be his peculiar people, as he hath promised thee, and that thou shouldest keep all his commandments; And to make thee high above all nations which he hath made, in praise, and in name, and in honour; and that thou mayest be an holy people unto the Lord thy God, as he hath spoken”- Deuteronomy 26: 17-19, KJV