Chasidut for Bava Kamma 127:16

An alternative explanation to the 13 attributes of G’s listed by ‎the Torah in our portion. It is an accepted rule that the written ‎Torah may be studied and understood better by using the 13 ‎principles of Rabbi Yishmael that we recite in our prayers every ‎morning. The 13 attributes of G’d that Moses lists in our portion ‎may be understood as corresponding to this. The exegetical tool ‎described as ‎בנין אב‎ in Rabbi Yishmael’s list (# 3 in that list) is ‎none other than ‎חן‎, “grace.” We, the Jewish people, enjoy grace in ‎the eyes of the Lord. Let us clarify this by means of a parable. If a ‎young child says something clever, the father is pleased to hear ‎this and he enjoys this even if he is aware that the clever saying ‎had not originated in the mind of the child itself, but reflects ‎something that his mother had taught him. The father, in spite ‎of his intellectual superiority to his child, “lowers” himself to the ‎child’s level in order to enjoy his child’s achievement. The reason ‎he does so is because there exists a bond between a father and ‎child called ‎חן‎, “grace or charm.” When G’d “restrains Himself,” as ‎we pointed out repeatedly, one of the reasons is also that He ‎relates to His Children of Israel like a father, and this bond of ‎חן‎ ‎exists between them. The reason why the third of the 3 categories ‎of valid exegetical tools in Rabbi Yishmael’s list is called ‎בנין אב‎, ‎‎“basic rule,” is that it parallels this “given” (rather than acquired) ‎relationship between a Creator and His derivative, i.e. His child, in ‎this case His brainchild.‎
Let us now look at Rabbi Yishmael’s fourth category of ‎legitimate exegetical tools, the one known as ‎כלל ופרט‎, ‎generalities and specifics (or the reverse.) This principle ‎corresponds to the Divine attributes of ‎ארך‎ and ‎אפים‎, respectively. ‎In order to understand this, we will again resort to a parable. A ‎father, regardless of his son’s intelligence, loves him loyally as his ‎flesh and blood. A similar relationship exists between G’d and His ‎‎“children,” [seeing He is a partner in any human being, ‎having supplied one third of its components by contributing the ‎soul. Ed.] There is another aspect to this love of father ‎for son; because he loves him he constantly tries to teach him so ‎that he will become more intelligent and more mature mentally. ‎This aspect of parental love is known as ‎כלל ופרט וכלל‎.
Let us know explain the Divine attribute of ‎ארך‎, i.e. that G’d ‎loves us regardless of whether we are intelligent enough to realize ‎that we ought to revere Him and to love Him, He does not ‎withdraw His love from us. It follows that the attribute of ‎ארך‎ ‎corresponds to the exegetical tool of Torah exegesis known as ‎‏ כלל ‏ופרט‎, relating collective terms to specific terms.
The Divine ‎attribute of ‎אפים‎, is how G’d, out of His love for us, teaches us ‎how to serve Him, so that the combined attributes ‎ארך אפים‎, ‎correspond to Rabbi Yishmael’s exegetical tool known as ‎כלל ופרט ‏וכלל‎, establishing harmony between collective terms and specifics, ‎so that they do not contradict one another. This is why the ‎Talmud in Baba kamma 54 describes the latter ‎כלל ‏‎, as ‎adding an additional element.‎[I have not understood the Talmud there in that way. ‎Ed.]‎‎ ‎