‘ Then the children of Reuben, and the children of Gad, and the half tribe of Manasseh, answered, and spoke to the heads of the sub-tribes (thousands) of Israel, “God, the God YHWH, God, the God YHWH, he knows, and Israel, he will know, if it be in rebellion, or if in trespass against YHWH, (do not save us this day), that we have built ourselves an altar to turn away from following YHWH, or if to offer on it burnt offering or meal offering, or if to offer sacrifices of peace offerings on it, let YHWH himself require it.” '
We should probably translate ‘El Elohim YHWH' as ‘God, the God YHWH' emphasising His uniqueness or as ‘God of the elohim (angels), YHWH' stressing His greatness rather than as ‘the God of gods, YHWH'. Either way the stress is on the fact that He knows men's minds and therefore knows that their own particular thoughts are innocent. The repetition of the name stressed the intensity of their feeling. This was the land of El, the head of the Canaanite pantheon, and here Israel claimed it for YHWH their God as the true El.
On the other hand Israel yet awaits that knowledge in the future. They have yet to learn the truth. But they will know. And what will they know? Whether they have built the altar in rebellion and disobedience to God's Law in order to offer offerings and sacrifices on it, thus being seen as turning away from following YHWH, or not. Note the acceptance of the idea that to build an altar other than at the revelation of YHWH, in order to offer sacrifices on it, was rebellion and disobedience. Israel could not set up altars at will like the Canaanites did. Only altars in places where God had recorded His name (patently revealed Himself) were acceptable, and especially that at the central sanctuary.
Their words were doubly emphasised by expostulations - ‘do not save us this day!' and ‘let YHWH Himself require it!' This reveals their agitation and calls on their listeners to recognise the genuineness of their declaration by their act of calling on YHWH to punish them if they were lying.
Note again the use of eleph for sub-tribes, which could also be translated ‘thousands'. The basic idea behind ‘a thousand' at this early date is that of a subgroup rather than a specific number. Note also the different offerings mentioned, burnt offerings, meal offerings and sacrifices of peace offerings.