Pseudo Jonathan Genesis 21:9
And Abraham was the son of an hundred years when Izhak his son was born to him. And Sarah said, The Lord hath done wondrously for me; all who hear will wonder at me. And she said, How faithful was the messenger who announced to Abraham, and said, Sarah will nurse children, for she shall bring forth a son in her old age! And the child grew and was weaned. And Abraham made a great feast on the day when Izhak was weaned. And Sarah observed the son of Hagar the Mizreitha, whom she bare to Abraham, mocking with a strange worship, and bowing to the Lord. And she said to Abraham, Cast out this handmaid and her son: for it is not possible for the son of this handmaid to inherit with my son; and he to make war with Izhak. And the thing was very evil in Abraham's eyes, on account of Ishmael his son, who would practise a strange worship.
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