Chronological difficulties are frequently explained in the Sources by the concept of אין מוקדם ומוחר בתורה -- Ein Mukdam U'm'uchar Ba'Torah -- There is no before and after in Torah.
(1) Where is the original expression of this concept? You'll find it in various places (Mechilta de Rabbi Yishmael 15:9, Sifrei_Bamidbar 64:1, Ruth_Rabbah 4:5), but where is the first? Is it used or at least mentioned in the Talmud ?
(2) What does it really mean? That the creation of the world might have happened after the Exodus from Egypt? That Jacob was born before Abraham? That Moses died before he was born? Surely not. So what are the limits of this concept?