Above all things (pro pantōn). See this phrase in Jam 5:12.
Being fervent (ektenē echontes). Present active participle of echontes and predicate accusative of adjective ektenēs (from ekteinō, to stretch out), stretched out, here only in N.T., “holding intent you love among yourselves.”
For love covereth a multitude of sins (hoti agapē kaluptei plēthos hamartiōn). See Jam 5:20 for meaning, sins of the one loved, not of the one loving.