R. Joseph B. Soloveitchik, The Lord is Righteous in All His Ways: Reflections on the Tish`ah be-Av Kinot, p. 131:
At the very dawn of creation, when Ha-Kadosh Barukh Hu consulted with the angels, as it were, as to whether or not He should create man, there was a disagreement in the heavenly court. The Midrah (Gen. Rabbah 8:5) says that the heavenly hosts were divided into different groups... [T]ruth was opposed, because, it said, man is basically a liar (she-kulo shekarim)... Peace was opposed because, it maintained, man is full of strife (dekhula ketatah). Truth and Peace were against the creation of man... Why were Truth and Peace opposed?
I once heard from my father zikhrono livrakhah, may his memory be for a blessing, that man can be either a perfect man of truth or a perfect man of peace, but he cannot be both at the same time. A man of truth does not know the secret of compromise...
In olam ha-zeh, this world, there is a conflict between truth and peace... But in the messianic era, the conflcit will be removed. This is what the verse means when it says "And love truth and peace." To be complete, man will not have to sacrifice either truth or peace, but will be able to act fully in accordance with both.