The souls conflict and deliverance

"Objection [To quieting the spirit in the soul's conflicts].  But I have often relapsed and fallen into the same sin again and again.
Answer.  If Christ will have us pardon our brother seventy-seven times, can we think that he will enjoin us more than he will be ready to do himself, when in cases of showing mercy he would have us think his thoughts to be far above ours?"

(From: The Soul's Conflict With Itself - Richard Sibbes)

There is a worship song that has a line '1000 times I fail yet your mercy remains.'
Of course like Paul we must ask:

"What shall we say then? Shall we continue in sin, that grace may abound? God forbid. How shall we, that are dead to sin, live any longer therein?" (Romans 6:1,2)

However, note that being a Christian does not suddenly mean we are completely perfect and won't make any mistakes along the way. Paul also admits:

“For the good that I would I do not: but the evil which I would not, that I do.” (Romans 7:19)

God looks at the heart. A good self examining question is to consider 'do I love sin?' Or 'Do I desire to be free of it for the sake of my first love Christ Jesus?'

One thing that is certain is that if we truly love Jesus we will not want sin any more and will come to loath our sins (even pet ones that need His special grace to be done with). Furthermore if this is the case it is also certain that His desire will be to lavish us with His forgiveness as we come to Him in sorrow and repentance. 

"If Christ will have us pardon our brother seventy-seven times, can we think that he will enjoin us more than he will be ready to do himself, when in cases of showing mercy he would have us think his thoughts to be far above ours?" (Sibbes)