Passage
And to me how precious have been Thy thoughts, O God, how great hath been their sum!
And to me how precious have been Thy thoughts, O God, how great hath been their sum!
Psalms 139:15 My substance was not hid from Thee, When I was made in secret, Curiously wrought in the lower part of earth.
Psalms 139:16 Mine unformed substance Thine eyes saw, And on Thy book all of them are written, The days they were formed--And not one among them.
Psalms 139:17 And to me how precious have been Thy thoughts, O God, how great hath been their sum!
Psalms 139:18 I recount them! than the sand they are more, I have waked, and I am still with Thee.
Psalms 139:19 Dost Thou slay, O God, the wicked? Then, men of blood, turn aside from me!
The verse centers on "precious", "been", "thoughts", "great", and "hath". It is saying that the verse draws attention to "precious" and "been", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 16's "Mine unformed substance Thine eyes saw And..." into verse 18's "I recount them than the sand they...", so "precious" and "been" belong inside that flow. In Psalms context, the local focus is worship, trust, the LORD's kingship, and covenant mercy.
A plain takeaway is to answer the verse's own emphasis on "precious" and "been" with trust shaped by these words, not by a vague optimism outside the passage.