Many people will be familiar with the phrase from Isaiah 28:10:

For precept must be on precept, precept on precept; line on line, line on line; here a little, there a little. (Isaiah 28:10)

This is widely used as a biblical learning curriculum, a concise expression of how the bible should be studied and learned.  It seems to make good sense.  Making an analogy with mathematics – you would not try to teach the concept of algebra without first ensuring that there was an understanding of at least addition and multiplication; the basic precepts of addition and multiplication come first, upon which the precept of algebra can be based.
Until recently this was my understanding of this verse.  As with others, I too would use the phrase, “Precept must be on precept, line upon line” to explain how one should use the bible to gain wisdom.  However, my understanding of this phrase recently underwent a major overhaul while listening to one of Michael Rood’s talks.  As he would put it, I had a, “Rood[sic] awakening!”  This phrase in Isaiah is actually used in a negative sense or as an admonition, which should have been obvious from the context of Isaiah chapter twenty-eight, but it is clearly expressed as such when it is again repeated in verse thirteen of the chapter:

Yet the word of Jehovah was to them, precept on precept, precept on precept; line on line, line on line; here a little, there a little; that they might go, and stumble, and be broken, and snared, and taken. (Isaiah 28:13)

We see that the result of this use of YHVH’s word is not a good one. The people were to suffer dire consequences because of their misuse of YHVH’s scripture.  They would stumble and be broken.  Their failure would lead to them being fooled and captured. No positive slant can be put upon these outcomes, and yet time after time we have wished them upon ourselves by invoking the curse to which they are linked.
Isaiah 28:13 can be recognised as a definitive focal point of the chapter as a whole and we can then look at the chapter and see that it is actually a warning, a reproof.  It talks about the leaders of the people, the priests and the prophets, being drunkards (Isaiah 28:7) and in their muddled state teaching the people.  The question is posed, whom could such a teacher instruct when in such a state – babies and infants? (Isaiah 28:9) Some say that Isaiah 28:9 is referring to YHVH as the teacher, however, YHVH does not work this way (Exodus 20:19).  He speaks to the prophets, and they are the ones who teach and explain, further to that it was the job of the priests to teach the law to the people (Leviticus 10:8-11, Deuteronomy 24:8; 33:8-10).
It is in the next verse that the drunken teaching phrase:

For precept must be on precept, precept on precept; line on line, line on line; here a little, there a little. (Isaiah 28:10)

is first used.  The passage continues:

For with stammering lip and another tongue, He will speak to this people; to whom He said, This is the rest; cause the weary to rest. Also, This is the repose. But they willed not to hear. (Isaiah 28:11-12 [LITV])
 

Here it can be understood that YHVH describes the effort he puts into communicating with the people.  The word translated as “stammering” is the Hebrew word, “Laeg” which can also be translated as, “a foreigner”  (Strongs: 3934), so YHVH is saying here that He will try to speak to his people via foreigners speaking different languages.  Yet, despite His efforts, the people failed to understand His words (Isaiah 28:13).   This is how Paul renders this verse:

In the law it is written, With men of other tongues and other lips will I speak unto this people; and yet for all that will they not hear me, saith the Lord. (I Corinthians 14:21 [KJV]

(I have used the KJV rendering here rather than the LITV because it more accurately translates the Greek word, “Heteroglossos” which means, “other-tongued”, i.e. one who speaks a foreign language [Strongs Greek: 02084].  The LITV translates this word with the phrase, “By other tongues” which in addition to not being an accurate translation of the Greek, also does not properly fit with the context of the verse.)
Far from being a prescription for good bible instruction the concept of “Precept upon precept…” is described in Isaiah as the teaching of drunkards which should not be followed.  It leads ultimately to us making the “lie our refuge” and results in our “hiding in falsehood” (Isaiah 28:15), which is an apt description of the position of many church denominations today.  How then should we read the scriptures?  My personal feeling is that they should be read as a whole, allowing the spirit of what we read to flow through all of the scripture, rather than taking bits from here and there to build what we want. This is, perhaps, what we can understand from the latter verses of this chapter of Isaiah where we are given the correct way to learn:

Listen and hear My voice; pay attention and hear My word: (Isaiah 28:23)

An agricultural example is then given of a farmer who carefully prepares his soil for planting (Isaiah 28:24).  He then plants each type of crop in the correct way:

When he has leveled its surface, does he not strew black cummin, and scatter cummin, and place wheat in rows, and barley in its place, and spelt in its border? (Isaiah 28:25)

Different Hebrew words are used to describe the different ways that the crops are sown.  The wheat is not scattered, and the cummin is not placed in rows, and so on.  The example continues by telling us that the crops are also reaped in different ways:

For black cummin is not threshed with the sledge; nor is a cartwheel turned on cummin. But black cummin is beaten out with the staff, and cummin with the rod.  Bread is crushed, but not always does one thresh it with threshing; and he drives the wheel of his cart; and his horses do not beat it small. (Isaiah 28:27-28). 

In the same way Scripture is not to be used inappropriately, taking pieces from here and there and using them incorrectly.  Verses should not be taken from their proper places and applied to meanings for which they were not  made.
This is only my understanding of what is being said here, but make no mistake,  what is being said is important:

This also comes from Jehovah of Hosts, doing wonders in counsel, making sound wisdom great. (Isaiah 28:29)

So even if you do not agree with my interpretation, do take some time yourself to understand what YHVH is telling us.