Pseudo Jonathan Genesis 21:9
7 And she said, 'How trustworthy was the messenger who made an announcement to Abraham, saying “Sarah is destined to suckle children.” For she has borne him a son at the time of his old age.' 8 The child grew and was weaned; and Abraham made a great feast the day he weaned Isaac. 9 Sarah saw the son of Hagar the Egyptian, whom she bore to Abraham, sporting with an idol and bowing down to it. 10 And she said to Abraham, 'Cast out this maidservant and her son; for it is not possible that the son of this maidservant should inherit with my son and then make war with Isaac.'
Galatians 4:29
27 For it is written:“Rejoice, O barren woman who does not bear children; break forth and shout, you who have no birth pains,because the children of the desolate woman are more numerousthan those of the woman who has a husband.” 28 But you, brothers and sisters, are children of the promise like Isaac. 29 But just as at that time the one born by natural descent persecuted the one born according to the Spirit, so it is now. 30 But what does the scripture say? “Throw out the slave woman and her son, for the son of the slave woman will not share the inheritance with the son” of the free woman. 31 Therefore, brothers and sisters, we are not children of the slave woman but of the free woman.
Notes and References
"... Paul in this passage is using and will go on using in a metaphorical way all sorts of language which is normally meant literally. For example, when Paul speaks of the slave girl in vs. 30 he is not referring to a literal slave girl. The whole allegorical context of the discussion here leads one to expect a metaphorical use of verbs. In fact, Paul here is alluding to Genesis 21.8-14 which at most refers to Ishmael playing with Isaac, but we know that in early Judaism this verb was taken in a metaphorical sense to mean more than just 'to engage in recreation with', indeed it was seen to mean something hostile or malicious (compare Josephus Ant. 1.215; Targum Pseudo-Jonathan Genesis 21.9-11; Jerusalem Talmud Sota 6.6). My point is that the exegetical handling of this Genesis story in early Judaism already involved a metaphorical handling of the key verb. It would not be surprising if Paul followed along in that line ..."
Witherington, Ben Grace in Galatia: A Commentary on St. Paul’s Letter to the Galatians (p. 337) William B. Eerdmans Publishing Company, 1998