The simple explanation is that everyone who views himself/herself a Christian, partake of the emblems for forgiveness of sins and to advertise the death of their Lord. Remember, in Raymond Franz's time some Bethelites partook of the emblems after the memorial and in secret. This many believe is not only a prerequisite for the so-called remnant of the 144000 but for all Christians. Where do all this come from? The following is a quote of John (6:53) from the NET Bible footnote:
Unless you eat the flesh of the Son of Man and drink his blood. These words are at the heart of the discourse on the Bread of Life, and have created great misunderstanding among interpreters. Anyone who is inclined toward a sacramental viewpoint will almost certainly want to take these words as a reference to the sacrament of the Lord’s Supper, or the Eucharist, because of the reference to ‘eating his flesh’ and ‘drinking his blood’ (John 6:53ff.; cf. Matt. 26:26-28). But this does not automatically follow: By anyone’s definition there must be a symbolic element to the eating which Jesus speaks of in the discourse, and once this is admitted, it is better to understand it here, as in the previous references in the passage, to a personal receiving of (or appropriation of) Christ and his work. Notice that in John 6:54 (NET footnote) the result (has eternal life and I will raise him up at the last day) is produced by eating (Jesus’) flesh and drinking his blood. Compare John 6:40 where the same result is produced by “looking on the Son and believing in him.” This suggests that the phrase here (eats my flesh and drinks my blood) is to be understood by the phrase in John 6:40 (looks on the Son and believes in him).
However, many believe
that the above is no coincidence. This is the only place where the Apostle John
refers to the memorial (cf. John 6:70, 71). Jesus uses this very same
terminology when instituting the memorial of his death. Early on in his
ministry (already in John 6) he would be preparing the people for the
Eucharist. His intimate followers, later to be anointed with holy spirit, would
celebrate the memorial for the forgiveness of their sins and as participants of
the new covenant, prospective members of the 144000 (Matt. 26:28; 1 Cor. 11:25;
Rev. 14:1). Jesus’ earthly subjects would celebrate the memorial in remembrance
of their Lord and for the forgiveness of their sins. By doing this both groups
would be unified in “proclaiming the death of the Lord until he arrives” and
attaining the forgiveness of sins (Matt. 26:28; 1 Cor. 11:24-26; cf. John 6:56).