In the past decades, research has raised the idea of a theology of the Septuagint (LXX) on various occasions. Important works were recently published on this topic in the Handbuch zur Septuaginta and the Septuagint and Cognate Studies series. The general theological tendencies of the LXX are identified by scholars in eschatology, messianism, anti-anthropomorphism and angelology. These tend to all be regarded as further developments of the theology of the Hebrew Bible (HB). However, one can trace the evolution of these and other main topics of the LXX in the New Testament (NT) and in the later apostolic writings as well. Based on three concise case studies, I point out the evolution of theological ideas from the HB through the LXX up to the NT in this paper. First, I will discuss the importance of the ‘Name of God’-theology which is increasingly present in the LXX and has a key role in the messianic passages of the NT. Then in two points it will be argued that addressing Jesus as κύριος implies theological accents which can be detected in the LXX. These observations aim to show that the development of the religious ideologies of the HB can be followed not only in the LXX but in the NT and beyond as well. The importance of a theology of the LXX goes beyond the HB research, having significant implications for the NT as well. In fact, such theology could build the bridge between the HB and the NT, and should not only be written from the viewpoint of the HB but also considering the NT.