How we cite our quotes:
"Once upon a time, there were four girls, who had enough to eat and drink and wear, a good many comforts and pleasures, kind friends and parents who loved them dearly, and yet they were not contented." (4.60)
Love is an essential part of the family life of the March girls, but it's also not enough – at least, the love of parents and friends alone is not enough!
To others it might seem a ludicrous or trivial affair, but to her it was a hard experience, for during the twelve years of her life she had been governed by love alone, and a blow of that sort had never touched her before. (7.40)
Love is not just a fluffy feeling in the March household; it's also the center of morality. Amy has been "governed by love" instead of by the fear of physical punishment. Marmee (and, as we'll see later in the novel, Mr. March) uses love as a disciplinary tool.
"I gave my best to the country I love, and kept my tears till he was gone. Why should I complain, when we both have merely done our duty and will surely be the happier for it in the end? If I don't seem to need help, it is because I have a better friend, even than Father, to comfort and sustain me. My child, the troubles and temptations of your life are beginning and may be many, but you can overcome and outlive them all if you learn to feel the strength and tenderness of your Heavenly Father as you do that of your earthly one. The more you love and trust Him, the nearer you will feel to Him, and the less you will depend on human power and wisdom. His love and care never tire or change, can never be taken from you, but may become the source of lifelong peace, happiness, and strength. Believe this heartily, and go to God with all your little cares, and hopes, and sins, and sorrows, as freely and confidingly as you come to your mother." (8.88)
As Marmee explains to her daughters, she believes that one's love of God is the most important kind of love to feel, but that it has practical relationships to the love of one's country and one's family. By loving God more strongly than anything else, Marmee is able to sacrifice her love for her husband in order to further their loyalty to their country.