"[Samson] did not know that the Lord had left him" (Judges 16:20)
Any discussion of the baptism with the Holy Spirit and the power that results from it would be incomplete if attention were not called to how spiritual power may be lost.
"God withdraws His power from men when they go back on their separation" (Numbers 6:2; Judges 16:20). There was a day when Samson turned his back utterly upon the world and its ambitions, its spirit, its purposes. He separated himself to God, and God honored him with the anointing of His Spirit. But if he world recaptures his heart, the Lord leaves him.
Power is lost through the incoming of sin. King Saul wrought a great victory for God (1 Samuel 11:6-11), but then disobeyed (1 Samuel 13:13-14; 15:3-23), and God withdrew His favor and His power. Saul's history is mirrored in many lives of people whom God has once used. Sin has crept in, and the power of God has been withdrawn.
Power is lost through self-indulgence. The person who would have God's power must lead a life of self-denial. There are many things that are not sinful in the ordinary understanding of the word "sin", but which hinder spirituality and rob men of power. The gratification of the flesh and fullness of the Spirit do not mix (Galatians 5:17).
Power is lost through greed for money. It was through this that Judas Iscariot fell from the original apostolic company, and it is the love of money that is the root of all kinds of evil (1 Timothy 6:10). How often have people once known what spiritual power was, but money began to come, and little by little it took possession. Even when money is accumulated honestly, the love of it can absorb a person and shut the Spirit out.
Power is lost through pride. How often has a person become puffed up because God has given him power and used him, and God has been forced to set him aside as a proud man (1 Peter 5:5).
Power is lost through neglect of prayer and the Word of God. God's power is always linked to prayer and God's Word. How quickly do we run dry through their neglect. Let us return always to spend time on our faces before God.
Heavenly Father, help me to guard this marvelous gift of Your Holy Spirit. Even in this I will fail if I am left on my own. Whether it's carelessness with sin or a desire for self-indulgence or something else, keep my heart true to You. Amen
~R. A. Torrey~