Consider this prayer from the journal of evangelist and author of Pilgrims Progress, John Bunyan:

"After my previous repentance, there is again one thing which makes me sad; that is, if I most severely examine the best thing I am now doing, in it I discover sins, new sins mingled in the best thing I do. Therefore now, I cannot help but conclude that no matter how proud of myself and how idealistic I was concerning myself and my work, and even if my former living were without blemish, yet the sins that I commit in a day are enough to send me to hell. In such a deep feeling of sins, he cried out: “Unless He is such a great Savior, He surely cannot save such a great sinner as I."

or these words from John Knox as he lay upon his death bed:

"O Lord, have mercy on me, do not judge my innumerable sins; amongst them, may you forgive especially those sins which the world cannot reprove. In my youth, my middle age, and until now, how much conflict have I passed through. I have discovered that within me there is nothing besides falsehood and corruption. O Lord, only You are the Lord who knows the secrets of man’s heart. Please remember that of all the sins which I mentioned, not one of them is pleasing to me. I often grieve over them: they are deeply hated by my inner man. Now I weep sorrowfully for my corruption. I can only rest simply in Your mercy."

And we 'Christians' of the twenty-first century walk an aisle, say a prayer, are baptised, then walk right back into the world - without repentance, without change, without grief over our sins - then wonder why we have no power to overcome when the trials and testings of our faith come like roaring lions into our lives.

We have forgotten, perhaps we never knew: Salvation is a process, not a one time thing. 

"And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what [is] that good, and acceptable, and perfect, will of God."  Romans 12:2