Pray Without Ceasing?

The Apostle Paul boldly claims that the will of God for us is to PRAY WITHOUT CEASING, among other things (1 Thessalonians 5:16-24).  But what does he really mean and how is such a mandate possible?  Today I appreciated the notes on verse 17 from the ESV Study Bible:

"Pray without ceasing suggests a mental attitude of prayerfulness, continual personal fellowship with God, and consciousness of being in his presence throughout each day."

The truth is, I am utterly and completely unable to truly live this way no matter how disciplined I try to be.  That is, this is impossible apart from the constant help of the Holy Spirit.  But then, it seems to me that this is the idea: continual communion with the Lord, empowering from the Spirit, utter and total dependence on God.  The more I learn, the more that I experience, the older I become, the more I realize that I am weak, my heart is prone to selfishness, pride, independence from God... I frequently (more than just once daily) need to consciously acknowledge that I need Jesus, that I need the empowering of the Holy Spirit to help me to love, to obey Him, to serve well.  Because I know I cannot do any of this without Him, I must humble my heart before God and invite Him to keep me mindful of my need.  I invite Him to remind me to pray for His leadership in my thoughts, words, and actions.  I invite Him to live this day with me, to lead me in every way.  And my heart thrills at the knowledge that He actually wants to live this day with me, by my side, in constant communion.