To disinterested professing Christians, Jesus has this to say:
"These people draw near to Me with their mouth,
And honor Me with their lips,
But their heart is far from Me."
- Matt 15:8
If the fire for Jesus has gone out in your life -- or is fading away as life takes its toll on us all, stop what you're doing and pray. "LORD, help my unbelief." It isn't something one can do on one's own.
Walter Martin used to love to quote D. L. Moody who was once asked why he urged Christians to be filled constantly with the Holy Spirit. "'Well,' he said, 'I need a continual infilling because I leak!'"
“He who believes in Me, as the Scripture said, ‘From his innermost being will flow rivers of living water.'” - John 7:38
So be filled with His Spirit today.
"Therefore the Samaritan woman said to Him, 'How is it that You, being a Jew, ask me for a drink since I am a Samaritan woman?' (For Jews have no dealings with Samaritans.) Jesus answered and said to her, 'If you knew the gift of God, and who it is who says to you, ‘Give Me a drink,’ you would have asked Him, and He would have given you living water.' She said to Him, 'Sir, You have nothing to draw with and the well is deep; where then do You get that living water? You are not greater than our father Jacob, are You, who gave us the well, and drank of it himself and his sons and his cattle?' Jesus answered and said to her, 'Everyone who drinks of this water will thirst again; but whoever drinks of the water that I will give him shall never thirst; but the water that I will give him will become in him a well of water springing up to eternal life.'” - John 4:9-14