Trespass is defined as...
NT:3900
paraptoma (par-ap'-to-mah); from NT:3895; a side-slip (lapse or
deviation), i.e. (unintentional) error or (wilful) transgression:

KJV - fall, fault, offence, sin, trespass.

(Biblesoft's New Exhaustive Strong's Numbers and Concordance with Expanded
Greek-Hebrew Dictionary. Copyright (c) 1994, Biblesoft and International
Bible Translators, Inc.)

I think the underlying message here is also it is not enough to say one
believes, but puts those practices and precepts to use, lying down our own
selfish desires for God's will and desire. So what does all this mean? If
we do not forgive others their sins against us, God doesn't forgive our
sins against him, are we then saved? Scripture refers to his children's
sins being not "imputed" or tallied up against them. Forgotten in other
words, so if we do not forgive, ours are not forgiven, so they are
remembered, so we are not children of his? What yaw'l think.

Brad