AN, Conditional deferment
"In harmony with this [ie, the conditional deferment of the
return of Christ] is the significant occurrence of the Greek particle 'AN'
(Greek 'alpha nu') in practically every NT passage which speaks of the time of
the Lord's return. This small and practically untranslatable particle always
imports an element of contingency or doubt into any statement where it is
included, 'giving to a proposition or sentence a stamp of uncertainty, and mere
possibility, and indicating a dependence on circumstances' (Edward Robinson --
Lexicon).
"For instance, all the Synoptists include it in connection
with the statement, 'There be some of them which stand here which shall not
taste of death till ('AN', it may be) they have seen the kingdom of God come
with power.' [Mat 16:28; Mark 9:1; Luke 9:27; John 8:52] So also every NT
quotation of Psa 110:1 'until ('AN', ever) I make thy foes thy footstool'. [Mat
22:44; Mark 12:36; Acts 2:35; 1Co 15:25; Heb 1:13; 10:13] Specially forceful is
the following: 'Ye shall not see my henceforth, till ('AN', the time whenever
that may be) ye shall say, Blessed is he that cometh in the name of the Lord'
(Mat 23:39).
"Other passages which by the use of the same word suggest that
the time of the Lord's return would be dependent upon some unspecified
contingency are: Mat 10:23; 12:20; Luke 19:23; 1Co 4:5; 11:26; Jam 5:7; Rev
2:25" (WRev 269).
Along these same lines, BDAG has: "AN [alpha nu] is a particle
peculiar to Greek... denoting an ASPECT OF CONTINGENCY, incapable of translation
by a single English word; it denotes that the action of the verb is dependent on
some circumstance or condition; the effect of AN upon the meaning of its clause
depends on the mood and tense/aspect of the verb with which it is
used."