Rav Chaim Palagi zt'l writes (in Sefer Nefesh Kol Choli, Maareches Shin, Ois 53): “One who pursues peace will merit a long life, and his days will not be cut short."
He further writes (Siman 6, Ois 13) that one's love for his friends must emanate from his heart and soul. It should not be mere lip-service. He says that one should be especially careful about this during the time between Pesach and Shavuos (when the students of Rav Akiva died for not properly respecting each other).
He goes on to say: "I testify by the Heavens and earth that any place where there is to be found hatred and jealousy amongst brothers, partners, students, or those who serve the public – where each individual wants to bring down his friend and derive honor from his downfall – they will not emerge cleanly, G-d forbid. But the measure of goodness is bigger, so any place where people have love and warmth between them that emanates from the heart and soul, they will have long life and much success for them and their offspring eternally."
