Albert Barnes Commentary Psalms 139:16

"Thine eyes did see mine unformed substance; And in thy book they were all written, [Even] the days that were ordained [for me], When as yet there was none of them." — Psalms 139:16 (ASV)

Your eyes saw my substance, yet being unperfect - This whole verse is very obscure, but the “idea” in this expression clearly is, “Before I had shape or form you saw what I was to be.” The single word in the original translated “my substance, yet being unperfect,” is גלם gôlem. It occurs only in this place, though the verb—גלם gâlam—is found in 2 Kings 2:8, where it is used in reference to the mantle of Elijah: And Elijah took his mantle, and wrapped it together, etc. That is, he rolled it up, or he folded it.

The noun, then, means that which “is” rolled or wrapped together; that which is folded up, and hence, is applicable to anything folded up or undeveloped. It would thus most aptly denote the embryo, or the fetus, where all the members of the body are still folded up, or undeveloped; that is, before they have assumed their distinct form and proportions. This is undoubtedly the idea here. Before the embryo had any such form that its future size, shape, or proportions could be marked by the eye of man, it was clearly and distinctly known by God.

And in your book - Where you record all things. Perhaps the allusion here would be to the book of an architect or draftsman, who, before his work is begun, draws his plan, or sketches it for the direction of the workmen.

All my members were written - The words “my members” are not in the original. The Hebrew is, as in the margin, “all of them.” The reference may be, not to the members of his body, but to his “days” (see the margin on the succeeding phrase). And then the sense would be, all my “days,” or all the periods of my life, were delineated in your book.

That is, when my substance—my form—was not yet developed, when still an embryo, and when nothing could be determined from that by the eye of man as to what I was to be, all the future was known to God. It was written down—just what my form and vigor should be, how long I should live, what I should be, and what the events of my life would be.

Which in continuance were fashioned - Margin, “What days they should be fashioned.” Literally, “Days should be formed.” DeWette renders this, “The days were determined before any one of them was.” There is nothing in the Hebrew to correspond with the phrase “in continuance.”

The simple idea is that the days of my life were determined, and the whole matter was fixed and settled. This was not based on anything seen in the embryo, but “before” there was any form—before there were any means of judging from what I then was to what I would be. All was seen and arranged in the divine mind.

When as yet there was none of them - Literally, “And not one among them.” Before there was one of them in actual existence. Not one development had yet occurred from which it could be inferred what the rest would be. The entire knowledge on the subject must have been based on Omniscience.