Deuteronomy 6:4
2 and that you may so revere the Lord your God that you will keep all his statutes and commandments that I am giving you—you, your children, and your grandchildren—all your lives, to prolong your days. 3 Pay attention, Israel, and be careful to do this so that it may go well with you and that you may increase greatly in number—as the Lord, the God of your ancestors, said to you, you will have a land flowing with milk and honey. 4 Hear, O Israel: The Lord is our God, the Lord is one! 5 You must love the Lord your God with your whole mind, your whole being, and all your strength. 6 These words I am commanding you today must be kept in mind,
1 Corinthians 8:6
4 With regard then to eating food sacrificed to idols, we know that “an idol in this world is nothing,” and that “there is no God but one.” 5 If after all there are so-called gods, whether in heaven or on earth (as there are many gods and many lords), 6 yet for us there is one God, the Father, from whom are all things and for whom we live, and one Lord, Jesus Christ, through whom are all things and through whom we live. 7 But this knowledge is not shared by all. And some, by being accustomed to idols in former times, eat this food as an idol sacrifice, and their conscience, because it is weak, is defiled. 8 Now food will not bring us close to God. We are no worse if we do not eat and no better if we do.
Notes and References
"... Finally and most importantly, Paul applies to Jesus Christ, as well as to the Father, monotheistic language, which cannot be applied to any being other than the sole deity. Key elements of the monotheism schema of Judaism are present in the christological statement in 1 Corinthians 8:4–6. As we saw in chapter four, the monotheism schema was associated in Jewish sources with only the one God himself and certain hypostases, such as the wisdom and word of God, which were not clearly independent of God. Paul also calls Jesus Christ the ‘one Lord’, echoing the Shema ..."
Rainbow, Paul A. Monotheism and Christology in I Corinthians 8.4-6 (p. 173) The Queen's College, 1987