Are all Gentiles (non-Jews) Evil in the Old Testament? Was it fair for God to judge Gentiles in the Old Testament when they didn’t have His Torah (Law)? Did they even know who he was or that he was the real God?

I don’t think it’s beyond the scope to believe God had contact with Gentile nations before Christ. There are examples in the Bible of Gentile nations having interactions with YHWH directly (like Balaam) and indirectly (through a prophet like Jonah). Also, since we are all related (through Noah), they could have retained memories of the moral laws given between Adam and Noah’s time. Abraham himself is kind of a “Gentile” since Israel is his grandson, and the Sinaitic covenant, which distinguishes Jews from Gentiles, has not been given yet. Abraham is set apart by the command to circumcise in Genesis 17. 

In the story of Jonah, Jonah was told to go to prophesy to the Ninevites (in the Assyrian Empire). He disobeyed God and fled as a stowaway on a ship going in the opposite direction. God caused a storm to stop, and the Gentile sailors prayed to all their gods. When they learned from Jonah that it was his God, the God of Israel, who was causing the storm, they tossed him overboard (as he had instructed) and were spared. They praised and worshipped the God of Israel and promised to bring him a sacrifice for sparing them. Eventually, when Jonah preached to the Ninevites, they repented for their sins, and God spared them from his wrath. In addition, we see God communicate with Gentiles like in Job, the wicked prophet Balaam (Numbers 22-24), and Melchizedek, king of Salem, who was a high priest of God (YHWH) among the Canaanites (Genesis 14:17-20). God even contacted Nebuchadnezzar and sent him to conquer and exile the Israelites because of their sin. God even ensured that Nebuchadnezzar preserved Jehoiachin (son of Jehoiakim) by taking him captive to protect the line of David in exile.

Legal codes, such as the T’ien-ming (Chinese), Ur-Nammu (Sumerian), or Hammurabi’s Code (Babylonian), were Gentile versions of the Noahide covenant, holding Gentiles accountable for moral sins like killing, lying, and adultery. In the story of China, they are given the “T’ien-ming” or Mandate of Heaven, in the first dynasty known as the Xia. They were the first three dynasties, Xia, Shang, and Zhou, who incurred the wrath of a supreme being (the Shangdi) for failing to follow the Mandate. After the first three dynasties, the Shangdi took away the mandate of heaven and cursed China into a time of conflict called the Warring States period, which ended when China was reunited with the Qin (Chin) Dynasty, marking the beginning of Imperial China.

These moral laws pre-existed the Mosaic laws given to Moses for Israel and can be found in various legal codes in the Ancient Near East and worldwide. I believe the Gentile nations were held accountable to those moral standards but not responsible for the ritual purity laws or region-specific laws of the Bible. These laws were designed to set Israel apart and did not apply to the whole world. That is why some laws included accompanying text, such as: “These regulations apply both to the foreigners living among you and to the native-born Israelites.” Therefore, any law governing something like land ownership, sabbath years, or slavery wouldn’t apply to Gentiles living outside of Israel. These laws were specifically for the nation of Israel and couldn’t be enforced outside of Israel’s borders.

In Conclusion, one could infer that they were judged by the moral laws only, and those who kept those laws were considered righteous according to the Noahide covenant standards. Those righteous Gentiles from before Christ would likely have received Christ if they were alive in the 1st century, and it seems possible that while Christ was dead for three days, he ministered to them in the afterlife. This logic may also apply to Gentiles who were in regions that didn’t have access to the Gospel for many years, like the Americas, Australia, etc. God as a just ruler must have a system for those who would have received the Gospel if they had heard it but didn’t have a change or died before Christ came. Either way, they are considered worthy of participating in the first resurrection, which is reserved for the righteous (Luke 14:14, 1 Cor 15:12-58, 1 Thess 4:13-18, Heb 11:32-35, Rev 20:4-6).