Moffatt(i)
26 But the Jerusalem on high is free, and she is 'our' mother.
27 For it is written, Rejoice, O thou barren who bearest not, break into joy, thou who travailest not; for the children of the desolate woman are far more than of the married.
28 Now you are the children of the Promise, brothers, like Isaac;
29 but just as in the old days the son born by the flesh persecuted the son born by the Spirit, so it is still to-day.
30 However, what does the scripture say? Put away the slave-woman and her son, for the son of the slave-woman shall not be heir along with the son of the free-woman.
31 Hence we are children of no slave-woman, my brothers, but of the free-woman,