That the Gospel was preached in the form of promises made to the Jewish Fathers. The seed of the woman described in the judgements of God to the serpent refer to Christ. Promises given to Abraham, Isaac and Jacob, the Jewish fathers, and to King David all ultimately refer to Christ and to believers 'in Christ'.
The Old Testament contains this information together with teaching about Israel and the affairs of the world - particularly with reference to the time of the second coming of Christ. It is therefore important in providing us with this valuable information and should be read and studied.