The NKJV uses the term “at twilight” in place of “at even” in the KJV in some of the
Passover scriptures.  In Numbers 9:5 the Hebrew is “between the evenings”; in
Deuteronomy 16:6 the context clearly says that “at twilight” is at <toward> the going
down of the sun; and Joshua 5:10 “at twilight” cannot override the other two more
specific texts.

Numbers 9:5 And they kept the Passover on the fourteenth day of the first month, at twilight (between
the evenings),
in the Wilderness of Sinai; according to all that the LORD commanded Moses, so the
children of Israel did.

Deuteronomy 16:6 "but at the place where the LORD your God chooses to make His name abide,
there you shall sacrifice the Passover
at twilight, at the going down of the sun, at the time you came
out of Egypt.

Joshua 5:10  Now the children of Israel camped in Gilgal, and kept the Passover on the fourteenth
day of the month
at twilight on the plains of Jericho.

How can the Passover be slain <at> twilight and be <in> twilight.  If we point a stick at a
box, we are not pointing the stick in the box.  The problem is that we have a tendency to
want to prove our past traditions.  This stance gives the mind a problem and requires it to
come up with a solution.  The solution only needs to trick the mind into believing that all is
well with the current tradition.  This is a frightening reality of the mind.  For this
phenomenon to work, one has to approach the subject with the strong belief that what he
has already accepted cannot be false.  This sets up the mind to accept only what agrees
with the current theory.  

Here we are speaking of a simple, Basic English lesson.  Nevertheless, in the minds of
those who have been blinded by this <at twilight> theory, the word <at> does not mean
<at>, but <in>.  If we cannot get beyond a simple English lesson, how can we ever
understand complicated truths?  In fact, in the very seeds of this <at twilight> theory is
the proof that the Israelites
killed the Passover in the afternoon of the 14th.  However,
some have twisted it into meaning something, which the English Language does not

If the Passover was slain <at> twilight, this means that Passover was slain <before>
twilight – at means <toward>.  Now if Passover was slain <toward> twilight, we have
already proceeded too far if we wait until we are <in> twilight.  As the Passover was slain
<at> twilight on the 14th, this has to be in the afternoon of the 14th.  The only alternative
is <at> twilight on the 13th or 15th.  We know that the Passover was slain on the 14th.  
Christ was slain on the afternoon of the 14th so to a thinking mind, this is proof enough on
this issue.

It is true that <twilight> is after sunset.  However, when we consider the meaning of the
word <at> we see a new perspective.  <At>, according to the American Heritage
Dictionary means:
1) In or near the area occupied by; 2) To or <toward> the direction or location
of, especially for a specific purpose.
 Even <in> the area of twilight does not mean <in>
twilight.  The meaning is <toward> twilight or near twilight.  If you are already <in>
twilight, you are no longer <at> twilight.  The Israelites had to have enough time to get
the job done before twilight for they were to slay it <at> twilight.  Of course, this is a
quirk of the NKJV.  The term <at even> used in the KJV is more correct.  However, the
Hebrew term “between the evenings” is not only correct, but specific as well.