Aikido as explained by the Aikikai Foundation's website:
A pure budo comes with the unification of technique, body and heart. The budo, which will manifest itself, does not depend upon the technique, but rather upon the heart of the practitioner. The aim of Aikido is a kindness of heart expressed through this spirit of budo.
Here are some thoughts on the spirit of Aikido.
Aiki is love.
Budo is the path of the warrior. Combined with the spirit of heaven and earth in your heart, you can fulfill your life's destiny with unconditional love for everything.
Aiki seeks to skillfully strike down the ego and inherent insincerity in battling an enemy. Aiki is the path of forgiveness and enlightenment. The martial techniques provide discipline for the journey of uniting the spirit and the body through channeling the laws of heaven.
The goal of Aikido training is not perfection of a step or skill, but rather improving one's character according to the rules of nature.
One becomes "resilient" inside yet this strength is expressed softly. Movements found in nature are efficient, rational, and soft,while the center is immovable, firm, and stable. This principal of a firm center is universally consistent -- and must be true for each person. The culmination of Aikido is expressed by aligning one's center with the center expressed throughout nature.
Aikido movement maintains this firm and stable center with an emphasis on spherical rotation characterized by flowing, circular, dance-like motions. These pivoting, entering and circling motions are used to control and overcome the opponent. The principle of spherical rotation makes it possible to defend one self from an opponent of superior size, strength, and experience.
Although Aikido movements are soft, rational, and smooth as in nature, by applying a bit of force,these can become devastatingly effective. The gentle quality of Aikido makes it appealing to men and women and children regardless of age. It not only offers spiritual development but also provides exercise and teaches proper etiquette and behavior.
At the heart of Aikido is the Eastern concept of Ki --the universal creative principle. Aikido seeks to unite this universal Ki with the Ki (life force or breath) found within each person. Literally, Aikido translates as "the way of harmony with Ki"