We know that we have passed from death to life, because we love our brothers. Anyone who does not love remains in death.
1 John 3:14
What does it mean to love another person? Let me start by answering what it means to love oneself. The best definition of love I have heard is to desire and act for the good of whatever you are loving. So, in order to love something, you must know what is good for it, you must desire it, and you must work towards it.
More and more, I think the best way to love oneself is seek God. To desire to know him, to seek him with my whole heart, to learn rest in his word of love and peace over me, to submit to his will in patience and obedience, to delight in his presence, and to worship Him with ever growing intensity and passion. I believe true joy is found there.
I think to love another person is to desire those same things for them, and to act in ways that will help them down that path. The same thing that will bring me my highest good will also bring them their highest good: knowing Christ.
In order to love them, therefore, that means desiring that they would know Christ better, and to spend my time, energy, money, and whatever else towards that cause, praying for those things, encouraging them to seek God, challenging them to obey God, reminding them of the truth of the Gospel and the truth of who they are in Christ.
I do this a little, but a little is not enough for such a worthy endeavor. I am glad of this scripture to remind me that all the good things I desire for myself, I should desire for others, and I will seek to do this more.