{His lot was} (elache). Literally, {he obtained the lot}.
Second aorist active indicative of lagchan(935c), to obtain by lot,
a very old verb from Homer on. It is used either with the
genitive as here, or the accusative as in  Ac 1:17  2Pe 1:1 .
Papyri show examples with the accusative. It was only once in a
lifetime that a priest obtained the lot of going (eiselth(936e),
here nominative aorist active participle agreeing with the
subject of elache) into the sanctuary (	on naon, not 	o
hieron, the outer courts) and burning incense on the golden
altar. "It was the great moment of Zacharias's life, and his
heart was no doubt alert for the supernatural" (Ragg). The
fortunate lot was "a white stone" to which  Re 2:17  may refer.
{Burn incense} (	ou thumiasai). Here only in the N.T. Occurs on
inscriptions. Hobart finds it used by medical writers for
fumigating herbs. "Ascending the steps to the Holy Place, the
priests spread the coals on the golden altar, and arranged the
incense, and the chief operating priest was then left alone
within the Holy Place to await the signal of the president to
burn the incense. It was probably at this time that the angel
appeared to Zacharias" (Vincent).