We didn’t finish this verse last week, so let’s look at it again:

Peacemakers who sow in peace reap a harvest of righteousness.

A few translations, including the NASB and ESV, are wooden and clumsy, but this TNIV captures the Greek well (Greek: ?a?p?? de d??a??s???? e? e????? spe??eta? t??? p????s?? e??????).

The truly wise teachers pursue peace in peaceful ways. This is how I would sum up the point of this verse. Again — the wise person, in contrast to those who pursue strife through self-ambition, has the goal of peace and gets there through peaceful means (not violent means).

Some pursue peace — misunderstood as the absence of strife — through
suppression (and they get the absence of strife); some through violence
(and strife goes away); some through manipulation behind the scene (and
they get the absence of strife); and some through deception — and they
get it too. The problem is that peace is not the absence of strife but
the conditions of justice and love. Genuine peace comes only through
God’s genuine approach: peaceful means only permit genuinely peaceful
ends.

This is the same as Jesus: “Blessed are the peacemakers.”

Anger, James told us in James 1:20, does not yield peace or God’s righteousness/justice.

Isaiah 32:17: “The effect of righteousness will be peace,
   and the result of righteousness, quietness and trust forever.”