thus the of calmness is also connected to

peace: the calm person is always peaceful and the peaceful
person is also calm. The calm person, "He will not quarrel nor
cry out, Nor will anyone hear His voice in the streets." (Matt.
12:19), as was said about the Lord Jesus. Thus he lives
peacefully with people because he does not quarrel with anyone
or raise his voice at them, and because he does not solve his
problems with people by using force but calmness.
Peace may well be lost between one rude person and another,
but it is not lost between a rude person and a calm one, because
the calm one can withstand the rude.
It is rather like the saying that fire cannot be extinguished by
fire, but by water. If the calm person by his calmness can pacify
the rude, then it goes without saying that peace can exist
between two calm people.
Calmness is one of the manifestations of inner peace, it is also a
factor which contributes to it. Whoever maintains his calmness
maintains his inner peace.
3. The relationship between calmness and gentleness is
self-evident, since calmness is a branch of gentleness, or one of
its outward signs, so that one could say that they are
interchangeable. When you speak about the calm person, you
are also speaking about gentleness. The person who loses his
calm obviously loses his gentle temper. When we speak of the
relationship between calmness and gentleness, we are just
speaking about the relationship between the part and the whole.
22 tasbeha.org/content/hh_books/Calmness/index.html