John Gill Commentary Leviticus 23:36

"Seven days ye shall offer an offering made by fire unto Jehovah: on the eighth day shall be a holy convocation unto you; and ye shall offer an offering made by fire unto Jehovah: it is a solemn assembly; ye shall do no servile work." — Leviticus 23:36 (ASV)

Seven days you shall offer an offering made, by fire unto the
Lord
A burnt offering; what this was, and how many were offered on each day, see at large in (Numbers 29:13–34);

on the eighth day shall be an holy convocation unto you ;
(See Gill on Leviticus 23:35):

and you shall offer an offering made by fire unto the Lord ;
which was different from that on all the other days, being one bullock only (Numbers 29:35Numbers 29:36);

it [is] a solemn assembly ;
of all the people, when they were gathered together before the Lord. Some render the word used a "restraint" or "detention", and interpret it of restraining or detaining them from servile work, as in the next clause; so Aben Ezra and Gersom; but this sense seems to make that clause unnecessary and is never used elsewhere where that is:

you shall do no servile work [therein] ;
as on the first day; (See Gill on Leviticus 23:35).