Theological Exegesis on Exodus 19

5 Now therefore, if ye will obey my voice indeed, and keep my covenant, 

then ye shall be a peculiar treasure unto me above all people: for all the earth 

is mine: 6 And ye shall be unto me a kingdom of priests, and an holy nation. 

These are the words which thou shalt speak unto the children of Israel.

"In verse 5, YHWH explains to Israel the manner of the relationship with him in which they are invited to participate. It seems that on the condition of their being obedient and faithful to his covenant, certain blessings will ensue. Here is the core of the passage, which Muilenburg suggests exemplifies the covenant Gattung (larger theme or genre), consisting of a conditional statement promising divine favor for obeying YHWH's will or threatening punishment for disobeying. Muilenburg cites many examples of this type of speech. However, verses 5-6 appear to differ from his model in the aspect of "conditional promise," in that the relationship of protasis (the statement of condition) to apodosis (the result of meeting the condition) is not consequential. The connection is far more subtle. Rather, as Patrick puts it, "the protasis is a definition of the requirements of the position or vocation designated by the titles of the apodosis." Obedience is the basis for the identity of the covenant people. In other words, to be YHWH's own possession, his priestly kingdom and holy nation, entails submitting to his will. Israel is invited to accept this offer. Thus the "if" is not a conditional, suggesting cause and effect, but almost the reverse. It describes a logical relation between responsibilities and privileges, in which Israel is invited to participate.

"The statement that Israel will be a people treasured by YHWH, therefore, is not to be seen as a reward for obedience; rather, it is a consequence of the covenant that YHWH is making here. At some point in the future they will become a segullah, a "treasured possession"; exactly when (under what circumstances) this happens, and what it involves, remains  an open question. Clearly it describes Israel's relation to YHWH in comparison to that of other nations.

"Verse 6 begins with an emphatic "you yourselves." This does not merely underscore Israel's uniqueness as described in the preceding verse; it also underscores the choice of these particular descriptions for Israel, however surprising they may sound. Both descriptions present interpretive difficulties, which are examined in more detail below. It suffices to say here that all three titles in verses 5b-6a (segullah, mamleket kohanim, and goy qadosh, defined below) are assumed to be closely related and to develop progressively--from the first to the second to the third--in the intensity of their meaning. Each is a referent for the same subject: the communal house of Jacob, the collective sons of Israel (relative to all of YHWH's other peoples), to whom the whole discourse is addressed and who reply to the promise in unison.

"Although Moses transmits the message to the elders, it is reported in verses 7-8 that "all the people answered together," stressing again the socially equalizing character of God's appearance and the communal unity of purpose and desire. Their response to do all that YHWH's  has spoken presupposes verse 5a ("if you [plural] obey . . .") and can be understood only as a commitment to obey the covenant law. Dale Patrick suggests: "If our passage is an offer, then we would expect a response of acceptance or rejection, and the pledge of obedience constitutes an acceptance." This launches the relationship into effect: at the moment the people make this pledge, they become YHWH's own possession, his kingdom of priests, his holy nation. Following Buber's existentialist interpretation of Sinai, the covenant is "not a contract but an assumption into a life relationship." If they had refused to pledge obedience, there would have been no story to tell; the fact of the telling presupposed Israel as YHWH's people."

Jo Bailey Wells, "The Book of Exodus," A Theological Introduction to the Pentateuch: Interpreting the Torah as Christian Scripture, Eds. Richard S. Briggs and Joel N. Lohr (Grand Rapids, MI: Baker Academic, 2012), 71-72