"I will both lay me down in peace, and sleep: for thou, LORD, only makest me dwell in safety." (Psalm 4: 8)
The LORD keeps us in safety.
That word safety is "betach", or uttermost confidence, almost a state of complete carelessness
"Thou wilt keep him in perfect peace, whose mind is stayed on thee: because he trusteth in thee." (Isaiah 26: 3)
He keeps us in peace. It's not our job to hold onto Him. He holds onto us.
He keeps us in safety no matter what challenges may confront us:
"No weapon that is formed against thee shall prosper; and every tongue that shall rise against thee in judgment thou shalt condemn. This is the heritage of the servants of the LORD, and their righteousness is of me, saith the LORD." (Isaiah 54: 17)
"A thousand shall fall at thy side, and ten thousand at thy right hand; but it shall not come nigh thee." (Psalm 91: 7)
Check out this, too:
"For thou hast made him a little lower than the angels, and hast crowned him with glory and honour." (Psalm 8: 5)
"Crowned" is compassed, or surrounded. We are protected by His glory, His honor. Powerful stuff.
He keeps us in safety from times and elements, too:
"The sun shall not smite thee by day, nor the moon by night." (Psalm 121: 6)
"They shall not hunger nor thirst; neither shall the heat nor sun smite them: for he that hath mercy on them shall lead them, even by the springs of water shall he guide them." (Isaiah 49: 10)
Those springs of water are within everyone of us today, because of the Holy Spirit who lives in us (John 7: 36-38)
There is one other word: "only"
God does this, and He alone. We cannot find this safety in anything that we do. We cannot base this peace on our actions, or the opinion of others. What Jesus did at the Cross, the New Covenant (Hebrews 8: 10-12), that is the basis for our peace, and the certainty of His security in our lives!