"7 After this Jesus went about in Galilee. He would not go about in Judea, because the Jews were seeking to kill him. 2 Now the Jews' Feast of Booths was at hand. 3 So his brothers said to him, “Leave here and go to Judea, that your disciples also may see the works you are doing. 4 For no one works in secret if he seeks to be known openly. If you do these things, show yourself to the world.” 5 For not even his brothers believed in him. 6 Jesus said to them, “My time has not yet come, but your time is always here. 7 The world cannot hate you, but it hates me because I testify about it that its works are evil. 8 You go up to the feast. I am not going up to this feast, for my time has not yet fully come.” 9 After saying this, he remained in Galilee."
John 7:1-9
The NEB rendering of 3 and 4 reads much more graphically than the AV, and should be looked at for a deeper understanding of what was being said. Jesus’ brothers were exhorting Him to go into Judaea and chiding Him for remaining in seclusion if He really wanted to make a public impact. It is clear that they did not really understand what Jesus was about, and their lack of faith in Him (5) is a fairly unmistakable indication that they were to be classed with those in 2:23-25, so far as believing in Him was concerned. What is even more astonishing in these verses is to find that so considerable a scholar as William Temple should subscribe to the idea that the 'brothers' of Jesus could only have been half-brothers, sons of Joseph by an earlier marriage. Others suggest that the 'brothers' were really cousins. There is no evidence in Scripture to substantiate such assumptions. One sees of course why this unwarranted interpretation is put upon the plain text: it is that it is regarded as unthinkable that Mary should have ever had other children, after bearing Jesus. This, however, is a Catholic tradition, not a biblical one, and is based on the idea of the perpetual virginity of Mary. But why should it be thought that Mary must not have had any more children? It calls in question the whole point of the Incarnation to suppose any such thing. The birth of Jesus was unique; but it did not impose any magical incapacity on Mary to have any more family; it was at this one point - and this one point only - that the natural processes of conception were suspended. Thereafter Mary reverted to being an ordinary woman and an ordinary mother, and it is no reflection either on the reality of the miraculous conception of Jesus or of the activity of God in the Incarnation to say so. Mark in his gospel names the four brothers of Jesus, and adds that they had sisters. Surely the obvious interpretation is that they were natural brothers and sisters of our Lord. The doctrine of the real humanity of Christ commits us to such a view.