Those, who have realized how dangerous and evil is the life they lead, the devil succeeds in keeping in his power, mainly by the following simple but all-powerful suggestion: "Later, later; tomorrow, tomorrow." And the poor sinner, deluded by the appearance of good intention accompanying this suggestion, decides: "Indeed, tomorrow; today I shall finish what I have to do, and then, free of all care, will put myself in the hands of Divine grace and will follow unswervingly the path of spiritual life. Today I shall do this and that; tomorrow I shall repent." This is the net of the devil, my brother, with which he catches a great many, and holds the whole world in his hands.
The reason why this net catches us so easily is our negligence and blindness. Nothing but ...blindness can explain why, when the whole of our salvation and all the glory of God are at stake, we fail to use immediately the most easy and simple and yet the most effective weapon, namely: to say to ourselves, resolutely and energetically "This moment! I shall start spiritual life this moment, and no later; I shall repent now, instead of tomorrow. Now, this moment is in my hands, tomorrow and after is in the hands of God. Even if God will grant me tomorrow and after, can I be sure that I shall have tomorrow the same good thought urging me to mend my ways?" Moreover, how senseless it is when, for example, a remedy is offered for curing one's illness, to say: "Wait, let me be sick a little longer," And a man who delays the work of salvation does exactly this.
So, if you wish to be free of the prelest* of the enemy, take up at once this trusty weapon against him and obey immediately in actual deed the good thoughts and promptings coming from the Lord and calling you to repent. Do not in the slightest delay, do not permit yourself to say: "I have made firm resolve to repent a little later and I shall not abandon the intention." No, no, do not do this. Such resolutions have always proved deceptive and many people, who relied on them have for many reasons remained unrepentant to the end of their lives.
(To learn more about these questions, pick up a copy of Unseen Warfare by Saint Theophan the Recluse)
* prelest: spiritual self deception or delusion. We suffer from prelest when we believe we are making real spiritual progress, or when we trust in our own spiritual advice and direction.