Luke’s use and interpretation of his “Scriptures” in acts was investigated on the explicit quotations to be found within the Petrine and Pauline speeches. It became clear that this reflects a threefold problem which could best be described as texthistorical, methodological and hermeneutical in nature. It was established under the textcritical aspect of the problem, that Luke made use of the scrolls of the Torah, Isaiah, the Twelve Prophets and the Psalms. The reconstructed textreading of the Septuagint Textvorlage which he used for his explicit quotations in the Petrine and Pauline speeches, seldom differed from existing LXX texts. Those specific differences seem to be closer to the existing Hebrew versions. Pre-Lukan knowledge of some of the quotations could be found in other literature from early Judaism (especially in the Dead Sea Scrolls) and early Christianity (Paul, Mark and Hebrews), but convincing evidence was also found that Luke himself may have checked several of these quotations again and changed them when applying them in their new context. Two things pointed in this direction: (a) he sometimes quoted longer passages than those known from former traditions, as was the case in the quoted texts from Joel 2(3) and Psalm 15(16) in the second Petrine speech, and (b) he reflected knowledge of the broader context from which those quoted texts were TAKEN. The origin of the remaining quoted texts from the six speeches which were investigated, do not show sufficient proof to assume knowledge from existing written sources, and could therefore be ascribed to Luke himself. The investigation on the methodological aspect of the problem has confirmed that Luke’s explicit quotations are to be found, almost exclusively, in the speeches. His usage of his Scriptural quotations functioned on two levels: (a) and informative level, which focused on events from the past and which (especially) substantiated the events described in the Jesus-kerygma. They have a strong christological tendency, especially in the missionary speeches. But also (b) a normative level, which focused on the present and future and which is presented in a compelling manner to the current hearers (readers). It has a strong prophetic tendency. The hermeneutical aspect of the problem made it clear that Luke’s understanding of his Scriptures is to be placed within the broader frame of this presentation of the salvation-history. This is done from the perspective of a Theo-centric approach, in which God always remains the Subject, while it is being mediated in a pneumatological-prophetical manner by the prophets and fathers of old, and the apostles (here Peter and Paul) of the new age. They are capable and authoritative witnesses who could interpret those Scriptures. The content of the prophecy itself is presented in a kerygmatic form. It deals with specific themes which are coming from their real historical context and which are then related to God’s general and universal plan of salvation via the name of the “kurios”. The quotations function then within the aspects of the Lukan eschatology, Christology and soteriology.