There is a grammatical and theological problem that arises when we attempt to translate the text at Gen 22:18. This is because of the troublesome phrase "rehe thbaraku" which is the third person plural of the verb "Barak" meanining "to bless". The "th" prefix attached to the verb alerts us to the fact that we are dealing with a form of the Hebrew verb called "the hith'pael". And herein lies the problem. How does one translate the "hith'pael" here?
The hith'pael admittedly defines a reflexive form of a verb, so when used with "bless" it certainly may be translated as "bless themselves" and as a consequence several translations do this. [Cf Rotherham's, Jerusalem, Revised Standard, and at least one Jewish translation the "Tanakh].
But does this exhaust all discussion of the hith'pael here? If that is so, then why do a very large number of translations, certainly far in excess of those listed, translate the hith'pael here as a passive - "be blessed"? [Cf the NASB, NIV, NKJV, NLT, ESV, HSCB, and a whole swathe of others.] At first glance credence may be given to the argument that this is because these translations are reading back into the text a later Christian ethic based on the NT concept of faith based salvation, and not self-works.
This does not hold water, however, because there are significantly more Jewish translations who do the same here, that is, treat the hith'pael as a passive. [Cf JPS, Harkarvi, and Leeser]. Thus it appears that there is more that can be said about this Hebraic form. It is true that the hith'pael is the reflexive form of the Hebrew verb, and whereas it it is also true that the passive use is comparatively rare, it is also true that it is not impossible.
For instance, the hith'pael form of "barak" occurs on four occasions outside of this text in Genesis, and an examination of those translations that insist on a reflexive form at Gen 22:18, shows that at best, that their understamding of this form is in a state of flux and is not set in concrete as the Watchtower would suggest.
For instance, at Ps 72:17, the JB reversed itself and rendered the hith'pael as a passive here "Be blessed". But by far the most troublesome use of the hith'pael is found at Jer 4:2. The RSV says: "Then nations shall bless themselves in him, and in him will they glory". The problem here is that the hith'pael occurs twice: with "bless" [barak] and with "hal'al" meaning to "glory", "boast", "celebrate" etc. Thus to be consistent the RSV should have said "and in him will they glory themselves" Every translation I have read ignores the reflxive form at "halal" here. Except the NW "T".
The genius who "translated" this verse in the NW"T" has it this way: "They will boast about themselves" which is more paraphrase than translation.
Again an enormous problem occurs if one is to insist on the reflexive at Lev 14. In this chapter alone, the verb "Taher" meaning to "cleanse" occurs no less than 12 times in the hith'pael, and refers to the cleansing of a leper by the priest. Whereas, technically at least, the verb could be a reflexive, contextually this becomes highly improbable, given that the text clearly informs us that it is the priest who does the cleansing, and not the leper. Thus, the leper cannot at the same time "cleanse himself" if the verb is to be applied to the priest.
It becomes clear that the hith'pael here is used either as a middle form, "become clean" [as some translations do] or as a passive "be cleansed" [as most translations accept it]. For instance Rotherham has, at Lev 14:14, the following: "The priest shall put it upon the tip of the right ear of him who is to be cleansed" While Franz in his NW Confection has: "The priest must put it upon the lobe of the one cleansing himself..."
What is said of Rotherham here can be said of all the other translations uniformily. If anything comes out of this brief research, it is that, at the very least, any argument that insists on a uniform attribution of the reflexive to the hith'apel is tenuous at best. That other factors play a part cannot be ignored. It certainly may be reflexive, but the hith'pael does have, legitimately, other syntactical applications, hence the translation of Gen 22:18 as "be blessed" cannot be ignored, except by those who are blinded by their own dogmatism.
An excellent article, availabe for download on the web, is: "Abraham, Blessing and the Nations: A Philological and Exegetical Study" by Keith Nigel Gruenberg. Though not discounting the reflexive here, he argues persuasively for the passive.
Reinforcing this view is the way the ancient versions treat Gen 22:18. The Samaritan Pentateuch, the Aramaic Targums, the LXX and the Vulgate, all use the passive at Gen 22:18.
Finally. The greatest interpreter of this text at Gen 22:18, must according to those who believe in the Holy Spirit inspiration of the Bible, be the Holy Spirit Himself. He quotes this verse through Paul at Gal 3:8, and here He unerringly placed the passive form on the verb. The irony is that even Freddy Franz, chief architect of the NW "T" recognized this. Thus what is implicit in the Hebrew is made explicit in the Greek.
The truly ironic part is that the Watchtower, supposedly a "Christian" system of belief, has to revert to the OT, Jewish tradition, to prove its point while at the same time avoiding and even ignoring the clearer revelation of the Christian NT.
This is in itself a telling indictment of the Christian pretensions of the Watchtower. They are merely Pharisees, parading about as Christ's Sheep, people about whom Jesus warned us.