Do not lie to each other, since you have taken off your old self with its practices and have put on the new self, which is being renewed in knowledge in the image of its Creator. (Colossians 3:9,10 NIV)
Christ Himself, when He was here, never failed to let people know that when they entered that door, or that straight and narrow way, they were in for trouble. Now that may sound like a very terrible thing to say, especially to you young Christians who are not far inside the door, but be perfectly clear about it; the Lord Jesus never deceived anybody about this, never at all. He let people know that to “follow Him,” as He put it at that time, involved them in difficulty and suffering and persecution and trial and a lifelong thing. There is a cost here, a great cost. And we shall discover that while there are the compensations, for there are undoubtedly the compensations in this life and the mighty compensations for eternity, this is a way which is not easy for the natural man by any means. This work of the Holy Spirit is drastic, exacting, and very trying to the flesh. Make no mistake about it; it will take all the energy that the Holy Spirit Himself has to accomplish this work. It really will. So the Lord Jesus has not left us in any doubt about this.
But note, and I am glad the Apostle Paul puts it like this, because it is so true to experience, “The new man who is being renewed.” Notice, first there was a precise and definite transaction, “Ye put off” and “ye put on,” but now the work that is going on is not a single act of a single moment and a single day, but it is something that is going on in us.
2 Chronicles 31:21
He did it with all his heart and prospered.
This is no unusual occurrence; it is the general rule of the moral universe that those men prosper who do their work with all their hearts, while those are almost certain to fail who go to their labour leaving half their hearts behind them. God does not give harvests to idle men except harvests of thistles, nor is He pleased to send wealth to those who will not dig in the field to find its hid treasure. It is universally confessed that if a man would prosper, he must be diligent in business. It is the same in religion as it is in other things. If you would prosper in your work for Jesus, let it be heart work, and let it be done with all your heart. Put as much force, energy, heartiness, and earnestness into religion as ever you do into business, for it deserves far more. The Holy Spirit helps our infirmities, but He does not encourage our idleness; He loves active believers. Who are the most useful men in the Christian church? The men who do what they undertake for God with all their hearts. Who are the most successful Sabbath-school teachers? The most talented? No; the most zealous; the men whose hearts are on fire, those are the men who see their Lord riding forth prosperously in the majesty of His salvation. Whole-heartedness shows itself in perseverance; there may be failure at first, but the earnest worker will say, "It is the Lord's work, and it must be done; my Lord has bidden me do it, and in His strength I will accomplish it." Christian, art thou thus "with all thine heart" serving thy Master? Remember the earnestness of Jesus! Think what heart-work was His! He could say, "The zeal of Thine house hath eaten Me up." When He sweat great drops of blood, it was no light burden He had to carry upon those blessed shoulders; and when He poured out His heart, it was no weak effort He was making for the salvation of His people. Was Jesus in earnest, and are we lukewarm?