To give up a life of sin is like digging a well. At first only rubble is unearthed. Much effort and hard work is put in only to find metre after metre of dirt.
If you give up then, you will never strike water. If you persevere, you will, after some time, find a little wetness in the rubble. And, one day, with no warning, you will strike water. The water will gush forth and all around people, animals and the land will benefit from it.
In a similar manner, giving up sin is, initially, hard. If you pack it in as too difficult you will never reach the pureness of life without sin. Gradually it starts getting easier until, one day, the sweetness of a sinless life engulfs you. Then you become of benefit to everyone around you like the water in the well.