Passage
For there is not a word in my tongue, But, lo, O Jehovah, thou knowest it altogether.
For there is not a word in my tongue, But, lo, O Jehovah, thou knowest it altogether.
Psalms 139:2 Thou knowest my downsitting and mine uprising; Thou understandest my thought afar off.
Psalms 139:3 Thou searchest out my path and my lying down, And art acquainted with all my ways.
Psalms 139:4 For there is not a word in my tongue, But, lo, O Jehovah, thou knowest it altogether.
Psalms 139:5 Thou hast beset me behind and before, And laid thy hand upon me.
Psalms 139:6 [Such] knowledge is too wonderful for me; It is high, I cannot attain unto it.
The verse centers on "word", "tongue", "jehovah", "thou", "knowest", and "altogether". It is saying that the verse draws attention to "word" and "tongue", so its meaning should be read from those terms before moving to application.
The nearby context moves from verse 3's "Thou searchest out my path and my..." into verse 5's "Thou hast beset me behind and before...", so "word" and "tongue" 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 "word" and "tongue" with trust shaped by these words, not by a vague optimism outside the passage.