Jude is called the Lord’s “brother” in Matthew 13:55 and Mark 6:3. If this is the same Jude who wrote the epistle bearing that name (as many think), he calls himself “a servant of Jesus Christ and brother of James” (Jude 1:1). Now, suppose for a moment that he was Jesus’ blood brother. In that case, he refrains from referring to himself as the Lord’s own sibling (while we are told that such a phraseology occurs several times in the New Testament, referring to a sibling relationship) and chooses instead to identify himself as James‘ brother. This is far too strange and implausible to believe. Moreover, James also refrains from calling himself Jesus’ brother, in his epistle (James 1:1: “servant of God and of the Lord Jesus Christ”)...
Well not at all...A study of scripture reveals that Jesus put very little stock, if any at all in blood relationships...Including his own...What matters is the spiritual relationship in Jesus Christ...