Certain Hebrew words are retained in the body of the text of the Psalms, being transliterated instead of translated. Not forming any part of the title, super-scription, or sub-scription, they are considered here in a separate Appendix.
  They are two in number, that is to say, HIGGAION and SELAH, and we preserve the spelling of the Authorized Version for the sake of convenience.

I.  HIGGAION = SOLILOQUY.

  The word is found in three Psalms: namely 9:16; 19:14, and 92:3.
  In 9:16 it is transliterated "Higgaion".
  In 19:14 it is translated "meditation"; and
  In 92:3 it is rendered "solemn sound".
  The word occurs also in Lamentations 3:62, where it is rendered in the Authorized Version "device", and in the Revised Version "imagination".
  It is derived from hagah, and means to soliloquize, to speak to one's self; hence, to meditate (Joshua 1:8. So Psalms 77:12 and 143:5).
  As a noun, it would mean a meditation, or a speaking in premeditated words; and therefore worthy of memory or repetition.
  If the three Psalms be read in the light of this word, we shall note the subjects which are so worthy of our meditation, and not think about music.
  In Psalm 9:16 it is the judgment of Jehovah.
  In Psalm 19:14 it is the words and the work of Jehovah.
  In Psalm 92:2, 3 it is the lovingkindness and faithfulness of Jehovah.

II.  SELAH.

  This word may be from one of two roots; from salah = to pause; or from salal = to lift up.
  There is no need to descend to the guesses as to musical terms. A reference to Appendix 65 (page 1, Introduction Column 1) will lead us to connect it with subject-matter, not with music; and with truth, not with tunes.
  Some say it occurs always at the beginning of a strophe; others, always at the end. But this is a question of fact, and not of argument.
  The outstanding fact is that in four cases it comes in the middle of a verse, that is to say, Psalm 55:19; 57:3; and Habakkuk 3:3, 9.
  This is fatal to both theories, but yet it helps us to, and agrees with, the right conclusion, that both are the two halves of one truth. Selah does connect the end of one strophe with the beginning of the next; and, indeed, in four cases it connects the end of one Psalm with the beginning of the next, thus uniting the two Psalms (see Psalms 3 with 4; 9 with 10; 24 with 25, and 46 with 47).

  Selah, therefore, neither ends nor begins a passage, but it CONNECTS the two passages between which it is placed.
  An examination of each occurrence will show what this connection is. It is neither the pausing on one subject; nor the passing on from one subject to another: but it is the connecting of the two subjects together.
  Sometimes it is the Structures which are connected.
  Sometimes it is synthetic, and adds a development of thought by connecting a prayer with that which forms the basis of it.
  Sometimes it is antithetic, and adds a contrast.
  Or it connects a cause with an effect, or an effect with a cause.
  It is a thought-link, which bids us look back at what has been said, and mark its connection with what is to follow; or to some additional consequent teaching.
  Thus, if it be derived from salah, to pause, it is not the instruments of music which are to pause while the voices continue to sing; but it is our hearts which are to pause and to note the connection of precious truths.
  If it be derived from salal, to lift up, then, it is not the instruments which are to lift up their sound in a louder degree, but our hearts which are to be lifted up to consider more solemnly the two truths which are about to be connected.
  These connections, showing the importance and object of each "Selah", are given in the notes on each occurrence of the word.
  The phenomena connected with "Selah" may be thus stated:
  The word occurs seventy-four times in the Bible, and all are in the Old Testament.
  Of these, seventy-one are in the Book of Psalms, and three are in the model Psalm, "the prayer of Habakkuk", chapter 3.
  The use of the word is confined to thirty-nine Psalms out of the 150. In sixteen of these thirty-nine it occurs once (7, 20, 21, 44, 47, 48, 50, 54, 60, 61, 75, 81, 82, 83, 85, and 143): of these thirty-nine Psalms, thirty-one are in Psalms handed over to "the chief Musician". (See Appendix 64.)
  In fifteen Psalms it occurs twice (4, 9, 24, 39, 49, 52, 55, 57, 59, 62, 67, 76, 84, 87, and 88).
  In seven Psalms it occurs thrice (3, 32, 46, 66, 68, 77, and 140).
  In one Psalm it occurs four times, namely Psalm 89.

  It is distributed over the five Books of the Psalms (see page 720 in the Companion Bible) as follows:

Book I (1–41), seventeen times in nine Psalms.
Book II (42–72), thirty times in seventeen Psalms.
Book III (73–89), twenty times in eleven Psalms.
Book IV (90–150), four times in two Psalms.