13 Confidence in the Lord’s ability to discern and perceive the nature and needs of his people comes from a belief in God’s purpose. He is the Creator, and his creative concerns include individuals.
In a sense this section continues the emphasis on divine involvement by an emphatic use of “you” (ʾattâ, vv. 2, 13: “you know … you created”) and by the use of the pronominal prefixes and suffixes to the verbs and nouns in Hebrew (translated by “you” and “your”). The Lord has formed the individual as a spiritual (“you created [qānâ, GK 7865; Ge 14:22; Pr 8:22] my inmost being [‘kidneys’],” v. 13) and a physical being (“you knit me together”; cf. Job 8–11; Jer 1:5). All beings owe their existence to the Creator-God. How much more the individual who walks with God, who knows that the Lord has formed him or her for a purpose.
139:13 formed … wove. By virtue of the divinely designed period of pregnancy, God providentially watches over the development of the child while yet in the mother’s womb.
139:13 you formed my inward parts. God’s knowledge of the writer goes back even before his birth, to his conception, when the Lord created the psalmist’s personal existence.
knitted me together. The Bible speaks here as elsewhere of ultimate cause, not of proximate cause.
 VanGemeren, W. A. (2008). Psalms. In T. Longman III & D. E. Garland (Eds.), The Expositor’s Bible Commentary: Psalms (Revised Edition) (Vol. 5, p. 962). Grand Rapids, MI: Zondervan.
 MacArthur, J. F., Jr. (2006). The MacArthur study Bible: New American Standard Bible. (Ps 139:13). Nashville, TN: Thomas Nelson Publishers.
 Sproul, R. C. (Ed.). (2015). The Reformation Study Bible: English Standard Version (2015 Edition) (p. 995). Orlando, FL: Reformation Trust.