“Fear is not in love. Instead, perfect love casts out fear, for fear pertains to punishment. And whoever fears is not perfected in love. Therefore, let us love God, for God first loved us” (1 John 4:18-19).
This passage primarily teaches us that ‘perfection’ is ultimately achieved by loving God without servile fear. Our actions and motivations should not stem from fear and scrupulosity, but rather from a genuine love of God and neighbour. Therefore we must constantly be vigilant in evaluating our actions in order to see if they are done out of love or fear. We must be converted in our hearts with love; the same as a new convert to the Catholic faith would be. If we are constantly doing actions out of fear, we will not be converted in our hearts out of love.