Psalm 51:5

 Psalm 51:5

Behold, I was shapen in iniquity; and in sin did my mother conceive me.

a. NASB 1995: Behold, I was brought forth in iniquity, And in sin my mother conceived me.  [New American Standard Bible 1995 (NASB1995) New American Standard Bible®, Copyright © 1960, 1971, 1977, 1995 by The Lockman Foundation. All rights reserved.]

b. NKJV: Behold, I was brought forth in iniquity, And in sin my mother conceived me. [Scripture quotations marked "NKJV" are taken from the New King James Version®, Copyright© 1982, Thomas Nelson. All rights reserved.]

c. Classic Amplified Bible: Behold, I was brought forth in [a state of] iniquity; my mother was sinful who conceived me [and I too am sinful].  [Amplified Bible, Classic Edition (AMPC) Copyright © 1954, 1958, 1962, 1964, 1965, 1987 by The Lockman Foundation]

d. Tehillim/Psalms [Because the first three verses of Psalm 51 in the Jewish Bible is one verse, verse 5 in our Bible is verse 7 in the Jewish Bible.]: Behold, in iniquity  was I fashioned, and in sin did my mother conceive me. [THE ARTSCROLL TANACH SERIES TEHILLIM / PSALMS PERSONAL SIZE EDITION VOL.1, VOL. II, VOL. III, VOL. IV, VOL. V. Ⓒ Copyright 1977, 1985, 1996 by MESORAH PUBLICATIONS, Ltd.]

e. ESV: Behold, I was brought forth in iniquity, and in sin did my mother conceive me.  [Scripture quotations are from the Holy Bible, English Standard Version, copyright © 2001, 2007, 2011, 2016 by Crossway Bibles, a division of Good News Publishers. Used by permission. All rights reserved.]

f. Unless otherwise stated, all Greek and Hebrew definitions are from Blue Letter Bible

1. “Behold, I was shapen in iniquity; and in sin did my mother conceive me.”

a. Behold [Strong: 2005 hên, hane; a primitive particle; lo!; also (as expressing surprise) if:—behold, if, lo, though.]

b. [I was] shapen [Strong: 2342 chûwl, khool; or חִיל chîyl; a primitive root; properly, to twist or whirl (in a circular or spiral manner), i.e. (specifically) to dance, to writhe in pain (especially of parturition) or fear; figuratively, to wait, to pervert:—bear, (make to) bring forth, (make to) calve, dance, drive away, fall grievously (with pain), fear, form, great, grieve, (be) grievous, hope, look, make, be in pain, be much (sore) pained, rest, shake, shapen, (be) sorrow(-ful), stay, tarry, travail (with pain), tremble, trust, wait carefully (patiently), be wounded.]

c. [in] iniquity [Strong: 5771 ʻâvôn, aw-vone'; or עָווֹן ʻâvôwn; (2 Kings 7:9; Psalm 51:5 [7]), aw-vone'; from H5753; perversity, i.e. (moral) evil:—fault, iniquity, mischief, punishment (of iniquity), sin.]

d. [and in] sin [Strong: 2399 chêṭᵉʼ, khate; from H2398; a crime or its penalty:—fault, × grievously, offence, (punishment of) sin.]

e. [did my] mother [Strong: 517 ʼêm, ame; a primitive word; a mother (as the bond of the family); in a wide sense (both literally and figuratively [like father]):—dam, mother, × parting.]

f. conceive [me] [Strong: 3179 yâcham, yaw-kham'; a primitive root; probably to be hot; figuratively, to conceive:—get heat, be hot, conceive, be warm.]

1). There is a Jewish tradition that says David’s mother tricked his father Jesse into thinking David was illegitimate, but there is no Scripture for it. Some commentaries associate the illegitimacy to Ruth (a Moabitess: (Deuteronomy 23:3, 4). 

2). The school of thought I lean toward is that David is referring to his being a descendant of Adam. I do not believe David was illegitimate.