Galatians 1:19
19But I did not see any other of the apostles except James, the Lordâs brother. NASB
But other of the apostles I saw none, saving James the brother of the Lord. Douay-Rheims
If read in context there are numerous other passages that tell us Joseph and Mary had other children on their own.
The Greek backs this up.
In Luke 2:7 the word prototokon, first among others, is used in describing Christ.
If the good doctor had wanted to indicate no other children would come from Mary he would have used monogenes, to refer to Christ.
The word monogenes means only, only begotten, unique. One of a kind. Definition from HELPS Word-Studies
I think with Luke being a doctor he would know about how couples have other children and if Joseph and Mary had had other children.
Means simply firstborn see my post 184 Colossians refers to Christ as the first born of the Father, Exodus 13:2 Sanctify unto me all the firstborn, whatsoever openeth the womb among the children of Israel, both of man and of beast: it is mine.
Means simply firstborn see my post 191 Colossians refers to Christ as the first born of the Father, Exodus 13:2 Sanctify unto me all the firstborn, whatsoever openeth the womb among the children of Israel, both of man and of beast: it is mine.