An observant reader noticed this. There is a good explanation, having to do with the grammar of what are called “that-clauses,” and especially “purpose and result clauses.”
The grammatical rules have changed since the early 16th century. Therefore in purpose and result clauses I updated the simple conjunction ‘that’ to the compound conjunction “so that.” An example is at Acts 3:19:
Tyndale: Repent ye therefore, and turn, that your sins may be done away when the time of refreshing cometh.
Updated: Repent therefore, and turn, so that your sins may be put away when the time of refreshing comes.
In modern English, we no longer use a simple “that” to introduce purpose or result clauses. For example, if I want to explain why I went to a certain store, I might say, “I went there so that I could check out their selection.” This is a purpose clause – it explains the purpose of going to the store. I would not say “I went there, that I could check out their selection.”
The general rule (only general, it has exceptions) is that you should not use a comma in purpose clauses, but do add a comma in result clauses:
Purpose clause: Jennifer explained the matter thoroughly so that they could understand.
Result clause: Jennifer explained the matter thoroughly, so that they finally understood.
It is not always easy to distinguish purpose clauses from result clauses.
Note also that in object clauses we do not need to change the conjunction:
Object clause: Jennifer explained that we don’t do this in modern English any more.
When I came to faith as an adult and began reading the bible, I found the biblical usage confusing. For some reason, most modern bibles do not update purpose and result clauses. People who grew up reading the bible may be used to the obsolete construction, but I am updating for everyone, and especially new Christians. Sometimes I think perhaps that is why the Lord had me come to faith as an adult – so that I would be able to recognize the issues for new Christians, who turn to the scriptures and want to understand them as fully as possible.