וַיֹּ֧סֶף אַבְרָהָ֛ם וַיִּקַּ֥ח אִשָּׁ֖ה וּשְׁמָ֥הּ קְטוּרָֽה׃
And Abraham took another wife, and her name was Keturah.
Targum Jonathan on Genesis
And Abraham added and took a wife, and her name was Keturah; she is Hagar, who had been bound to him from the beginning.
Targum Jerusalem
She is Hagar, who had been tied to him from the beginning.