Common sense and life experience would also tell us that we're very much capable of falling into sin, even after receiving that precious gift of grace. Grace will certainly strengthen us and equip us for our new, redeemed life as children of God, but we still have our free will, and must continue to ask God for help in our life's journey towards heaven. We grow in sanctity.
You are actually very misinformed and so is most of the church. THat is because the church has lost it’s way and lost the power of the holy spirit. If you would like that strength again, like you had as a child..go to fhu.com where the Be Still exercise will put you on the path to true freedom from sin. What you have done, unwittingly . is neutered the power of Jesus. Once the bad spirit is cleansed, and it takes some time often, then there simply is no more will to sin because it was ITS will to sin the whole time!
a. Whoever abides in Him does not sin: Since sin is lawlessness, a disregard for God (1 John 3:4), and since Jesus came to take away our sins (1 John 3:5), and since in Jesus there is no sin (1 John 3:5), then to abide in Him means to not sin.