In the following verse, the word <keep> is <6213> the parsing is (8799) the stem is Qal.  
Observe the words for yourself as to what they can mean.  There is not one of these
words which can mean <to eat> or <consume>.  However, the word <prepare> is there.  
What took place on the 14th in the afternoon was the slaying of the lamb and the putting
of the blood on the doorpost.  In addition, remember that if rites and ceremonies include
eating the Passover, the eating must be over by the end of “between the evenings.”  If
“between the two evenings” were from sunset to dark, the Israelites would have eaten
raw lamb for there would have been no more than a few minutes to roast it.  We discuss
this perspective because some early 14th Passover advocates use Numbers 9:3 to argue
that eating the Passover must take place on the 14th.  Their argument is that the
Israelites had to do everything that pertained to the Passover on the 14th.  However, they
conveniently ignore that this verse also stipulates that the timing the Israelites had for the
tasks of this passage was “between the evenings”.

Numbers 9:3 “In the fourteenth day of this month, at even (between the evenings), ye shall keep
<6213> (8799) it in his appointed season: according to all the rites of it, and according to all the
ceremonies thereof, shall ye keep <6213> (8799) it.”

06213 `asah {aw-saw'}

a primitive root; TWOT - 1708,1709; v

AV - do 1333, make 653, wrought 52, deal 52, commit 49, offer 49,
execute 48, keep 48, shew 43, prepare 37, work 29, do so 21, perform 18, get 14, dress 13, maker 13,
maintain 7, misc. 154; 2633

1) to do, fashion, accomplish, make

1a) (Qal)
1a1) to do, work, make, produce
1a1a) to do
1a1b) to work
1a1c) to deal (with)
1a1d) to act, act with effect, effect
1a2) to make
1a2a) to make
1a2b) to produce
1a2c) to prepare
1a2d) to make (an offering)
1a2e) to attend to, put in order
1a2f) to observe, celebrate
1a2g) to acquire (property)
1a2h) to appoint, ordain, institute
1a2i) to bring about
1a2j) to use
1a2k) to spend, pass

08799 Stem  - Qal
Mood  - Imperfect
Count - 19885

Let us look at the word, "rites" <02708>.  This word #02708 is translated "rites" one
time out of the 104 times this word appears in the Hebrew.  The lamb was to be slain and
the blood sprinkled against the altar according to the statutes of this particular event.  
This requires no <eating> of the lamb.

02708 chuqqah {khook-kaw'}

from 02706; TWOT - 728b; n f

AV - statute 77, ordinance 22, custom 2, appointed 1, manners 1,
rites 1; 104

1) statute, ordinance, limit, enactment, something prescribed
1a) statute

The word <ceremonies> <04941> appears 421 times in the bible.  Translated as
<ceremonies> it appears in the miscellaneous group for this word.  The word has nothing
in it that has anything to do with eating.  There were  <judgments> or <ordinances>
concerning the lamb.  How it was to be purchased, how it was to be brought to the temple,
how it was to have its throat slit, how it was to be skinned and prepared for cooking, how
it was to have its blood dashed against the altar.

The 14th day was the preparation day, as mentioned in the New Testament and as
common sense dictates.  There is a possibility that they began cooking some of the earlier
lambs on the 14th.  Nevertheless, the night of observation is the 15th.  That is the night of
the Passover Feast.

Exodus 12:42 It [is] a night to be much observed unto the LORD for bringing them out from the land
of Egypt: this [is] that night of the LORD to be observed of all the children of Israel in their

04941 mishpat {mish-pawt'}

from 08199; TWOT - 2443c; n m

AV - judgment 296, manner 38, right 18, cause 12, ordinance 11,
lawful 7, order 5, worthy 3, fashion 3, custom 2, discretion 2, law 2, measure 2, sentence 2, misc. 18;

1) judgment, justice, ordinance
1a) judgment
1a1) act of deciding a case
1a2) place, court, seat of judgment
1a3) process, procedure, litigation (before judges)
1a4) case, cause (presented for judgment)
1a5) sentence, decision (of judgment)
1a6) execution (of judgment)
1a7) time (of judgment)
1b) justice, right, rectitude (attributes of God or man)
1c) ordinance
1d) decision (in law)
1e) right, privilege, due (legal)
1f) proper, fitting, measure, fitness, custom, manner, plan

Do not let the two words "rites" and "ceremonies" mislead you.  These are poor choices
by the KJV translators – which they used only one time, each. Furthermore, the Hebrew
words occur <many> times in the Hebrew bible.