"Therefore know this day, and consider it in your heart, that the Lord Himself is God in heaven above and on earth beneath; there is no other." Deuteronomy 4:39

"The Lord Himself is God; there is none other besides Him." Deuteronomy 4:35

"I am the Lord your God, who brought you out of the land of Egypt, out of the house of bondage. You shall have no other gods before me." Deuteronomy 5:6-7

In context, Moses is speaking to the Israelites after their 40-year journey in the wilderness. They are ready to enter the land that God had promised them- but first, Moses takes the time to review their covenant with God and to remind them why obedience is so important. If you have read the OT, you know that the Israelites were very good at forgetting that God is sovereign- at every opportunity they conveniently "forgot" and worshipped other gods or idols, only to return to the God who loved them after trying or terrible circumstances. Sitting on the edge of the promise fulfilled, Moses reminds them of God's goodness, faithfulness, and- most importantly- holiness.

God has pledged Himself to the people who put their trust in Him. This is not to be taken lightly. These verses help me to remember that, even if I am not actively serving another "god", anything I place in my life that takes precedence over my relationship with Him is an idol that I am worshipping- and that is a form of betrayal to the God who loves me. I have to constantly re-evaluate my life to see if I am glorifying God with my speech and actions, and keeping Him as the God in my life above all else. Do I always get it right? Not hardly! But just as God constantly reminded the Israelites, He is faithful to remind us if we are faithful to listen.