Initially, it might seem that there is nothing whatsoever in common between Christianity and Humanism. Yet I propose otherwise.
Granted, Christianity is based upon a theistic worldview; while most Humanists maintain a secular perspective. And granted that Christians tend to interpret the Bible as sacred material; whereas Humanists rarely attach such sentiments to any writings whatsoever (although we typically value literature in general). And whereas Christians usually maintain the historicity of miracles; at least those which are recorded in the Bible, most Humanists reject such based upon our secular worldview. Yet these differences notwithstanding, I maintain that with reference to the most basic exercise of the human experience; that of social relations, Christianity and Humanism actually share core interests and concerns.
Humanism is the theory that the intellect, and sensitivity towards the suffering of others, are sure and certain guides to sufficiently regulate the human experience. Living in accord with reason and compassion then is to live as a Humanist. In this context, it seems evident that Humanism is by no means an ideology which is exclusive from the Christian faith, nor the latter from the former. For even the very namesake of the Christian faith himself lived as a Humanist. Regardless of whether Jesus was in fact a historical figure, or whether he was instead a mythical literary character; this much can be said on behalf of Jesus Christ: His was a life which exemplified the basic precepts of Humanism.
Jesus was an independent thinker who did not allow laws and tradition to surpass reason and practicality. When his disciples were hungry on a Sabbath day, and picked corn to fill their bellies, Jesus justified such as a practicality of the human experience, even reminding their authoritarian critics that the Sabbath was made for the benefit of man, and not vice versa. When Jesus saw those in need of medical care on the Sabbath, he healed them in defiance of and in spite of tradition.
Jesus was a practical man and one who was close to nature. His illustrations and his teachings were oftentimes based upon nature rather than upon a text. He reasoned with his hearers by challenging them to reason within themselves rather than to be merely lead around by authority figures and archaic traditions. Jesus chided his critics for utilizing their intellect to read the signs of weather patterns, yet failing to be able to figure out right from wrong by reasoning circumstances to such an end.
Jesus was a compassionate man, who realized the social responsibility to supply that which was lacking for those in need, not as an opportunity to capitalize upon the suffering of another for personal gain, but as the right thing to do. When his disciples reminded him of the hunger of the masses, rather than question the lifestyle or initiative of the people, Jesus fed them. When Jesus saw folks suffering and in need of medical attention, rather than inquiring as to their ability to pay for medical care or judging their worthiness and character, Jesus simply tended to their needs.
Jesus Christ; be he a literal historical character, or be he a literary mythical character was a man who was lead by his intellect, and who acted in accord with his compassion for the suffering others. In this regard, Jesus Christ may very well be the greatest of all examples of what it means to live as a Humanist.
It is my conclusion that the major distinctions between Christianity and Humanism are primarily differences related to mere tradition and doctrines. As to more practical concerns; namely those of social relations and human suffering, the common sympathies between the two philosophies are basically indistinguishable. Hence, if we would but dispatch with matters spiritual for the purpose of mutual cooperation; and then focus those efforts on the plight of the human condition, I am convinced that Humanists and Christians alike can do much to alleviate suffering among humanity.
And so the apparent antipathy between Christianity and Humanism being merely philosophical, I suggest that a pact of cooperative efforts for the common good would be a practical benefit for the entire global community, and at the same time an opportunity for Humanists and Christians alike to exercise their respective heartfelt convictions.