In Psalm 16, David is speaking by faith and from personal experience. Just like David, we should be placing our complete trust in God. Do we waver and vacillate in our faith when problems come? Or do we hide ourselves in the Lord and call out to Him as our refuge? David learned, from experience, that there was no one better to have at his right hand than God. When God is our ultimate source of confidence, strength, and power, the enemy will not be able to gain an entry point into our lives!

I have set the Lord continually before me; because He is at my right hand, I shall not be moved. Therefore my heart is glad and my glory [my inner self] rejoices; my body too shall rest and confidently dwell in safety. Psalm 16:8-9 (AMPC)