Excerpt from Vine's Dictionary
AGAPAO DEFINES CHRISTIANITY
The characteristic word of Christianity, [agapao] can be known only from the actions it prompts. God's love is seen in the gift of his Son...But obviously this is not the love of complacency, or affection, that is, it was not drawn out by any excellency in its objects...It was an exercise of the divine will in deliberate choice, made without assignable cause save that which lies in the nature of God Himself.
...In respect of agapao as used of God, it expresses the deep and constant love and interest of a perfect Being towards entirely unworthy objects, producing and fostering a reverential love in them towards the Giver, and a practical love towards those who are partakers of the same, and a desire to help others to seek the Giver.
JESUS IS AGAPAO PERSONIFIED
Love had its perfect expression among men in the Lord Jesus Christ...Christian love is the fruit of his spirit in the Christian.
Christian love has God for its primary object, and expresses itself first of all in implicit obedience to his commandments...Self will, that is self-pleasing, is the negation of love to God.
Christian love, whether exercised toward the brethren, or toward men generally, is not an impulse from the feelings, it does not always run with the natural inclinations, nor does it spend itself only upon those for whom some affinity is discovered. Love seeks the welfare of all and works no ill to any...love seeks opportunity to do good to all men and especially toward them that are of the household of the faith.