The rest of Psalm 139:1-12

Verses 7-10:
These verses are basically saying that God, Jesus, or the Holy Spirit is always with us. We can never "lose" him. It says in the footnotes of my Bible, "God is omnipresent. Because of this, you can NEVER be lost to His spirit." Then it says that wherever we go God is keeping an eye on us, and His hand is guiding and protecting us.

Verses 11-12:
Thsee verses are saying that sometimes we sin, and we may think,"God will never take me back." The truth is that God never left you!! God loves us so much that darkness mis light to Him when it comes to his children.

Extra:
In my Bible there is a footnote by verse 12 that says to look up Job 34:22. It says, "There is no dark place, no shadow, where evil doers can hide."