Hey Christy, what they're referring to would be the fullness of the doctrine versus what we were all typically taught in church buildings. For example, in the church buildings, we're taught that you forgive anyone and everyone no matter what, under any circumstance, and that typically comes from these two verses:
But if ye forgive not men their trespasses, neither will your Father forgive your trespasses.
-Mat 6:15
Then came Peter to him, and said, Lord, how oft shall my brother sin against me, and I forgive him? till seven times? Jesus saith unto him, I say not unto thee, Until seven times: but, Until seventy times seven.
-Mat 18:21-22
But as we are instructed in Isa 28:10, we are to read the Scripture here a little and there a little, meaning that we take verses in correlation with each other. So if we take what is in Matthew 18 and look at the correlating verses in Luke, we find this:
Take heed to yourselves: If thy brother trespass against thee, rebuke him; and if he repent, forgive him. And if he trespass against thee seven times in a day, and seven times in a day turn again to thee, saying, I repent; thou shalt forgive him.
-Luke 17:3-4
So as we can see, there are conditions. There is nowhere in Scripture where God requires that we do more than He does, and He does not forgive men unless they come to grief and sorrow of their wrongdoing; therefore, He requires no more or less of us, meaning that if a man repents, we ought to forgive him all his trespasses, but if he does not repent, we can simply let go of our bitterness and let God judge the matter, taking vengeance as He decides, trusting Him to do what is best.