Exodus 19:5
3 Moses went up to God, and the Lord called to him from the mountain, “Thus you will tell the house of Jacob, and declare to the people of Israel: 4 ‘You yourselves have seen what I did to Egypt and how I lifted you on eagles’ wings and brought you to myself. 5 And now, if you will diligently listen to me and keep my covenant, then you will be my special possession out of all the nations, for all the earth is mine, 6 and you will be to me a kingdom of priests and a holy nation.’ These are the words that you will speak to the Israelites.” 7 So Moses came and summoned the elders of Israel. He set before them all these words that the Lord had commanded him,
Malachi 3:17
15 So now we consider the arrogant to be blessed; indeed, those who practice evil are successful. In fact, those who challenge God escape!’” 16 Then those who respected the Lord spoke to one another, and the Lord took notice. A scroll was prepared before him in which were recorded the names of those who respected the Lord and honored his name. 17 “They will belong to me,” says the Lord of Heaven’s Armies, “in the day when I prepare my own special property. I will spare them as a man spares his son who serves him. 18 Then once more you will see that I make a distinction between the righteous and the wicked, between the one who serves God and the one who does not.
Notes and References
"... the ultimatum in Matthew 6:24, about the impossibility of serving two masters, epitomizes the point made throughout this section. One must choose between serving and loving God with all one’s heart, might, mind, and body, or alternatively serving and loving other gods. This instruction is tantamount to requiring one to consecrate all that one has and is to the Lord. The true heart dedicates all toward the kingdom. The pure eye does not deviate from the course that God has ordained. As servants of God, his followers have been marked as temple slaves, as a “peculiar people,” purchased by and belonging to him (laos periousious; laos eis peripoiēsin, Exodus 19:5; 23:22; Deuteronomy 7:6; Malachi 3:17; 1 Peter 2:9), and hence it would be a breach of contract or covenant to serve another lord.147 Thus, the Sermon on the Mount presupposes a totally committed community, one that is “prepared to take responsibility for the consequences of the teaching of Jesus, even if it means their lives.” ..."
Welch, John W. The Sermon on the Mount in the Light of the Temple (p. 154) Ashgate, 2009