I am interested not in converting other people to Buddhism but in how we Buddhists can contribute to human society, according to our own ideas. I believe that other religious faiths also think in a similar way, seeking to contribute to the common aim....
Just as Buddha showed an example of contentment, tolerance, and serving others without selfish motivation, so did Jesus Christ. Almost all of the great teachers lived a saintly life - not luxuriously like kings or emperors but as simple human beings. Their inner strength was tremendous, limitless, but the external appearance was of contentment with a simple way of life.
...the motivation of all religious practice is similar - love, sincerity, honesty. The way of life of practically all religious persons is contentment. The teachings of tolerance, love, and compassion are the same. A basic goal is the benefit of humankind - each type of system seeking in its own unique ways to improve human beings. If we put too much emphasis on our own philosophy, religion, or theory, are too attached to it, and try to impose it on other people, it makes trouble. Basically all the great teachers, such as Gautama Buddha, Jesus Christ, or Mohammed, founded their new teachings with a motivation of helping their fellow humans. They did not mean to gain anything for themselves nor to create more trouble or unrest in the world.
Most important is that we respect each other and learn from each other those things that will enrich our own practice. Ever if all the systems are separate, since they each have the same goal, the study of each other is helpful.
A Policy of Kindness

Now, as [in the past], the concept of a transcendent god as creator has a powerful and inspiring impact on the lives of those who believe in it. The sense that their entire destiny lies in the hands of an all-powerful, omniscient and compassionate being leads them to try to understand the workings and key message of this transcendent being. Then, when they come to realise that this transcendent being embodies love and infinite compassion, they try to cultivate love and compassion towards their fellow beings as the qualities through which to express love for their creator. They also gain confidence and inspiration through a sense of intimacy or connectedness to this loving, transcendent being.
Although, metaphysically speaking, Buddhists reject any notion of a transcendent creator or god, some individual Buddhists do relate to certain higher beings, such as the goddess Tara, as an independent and real being with power over their destiny. For these practitioners Tara is their sole refuge, their greatest object of veneration and their trusted guardian and protector. What this suggests is that the inclination to seek refuge in an external source is something deeply natural for us as human beings.
But it is also clear that for other people the metaphysical concept of a transcendent being is unacceptable. Questions form in their minds, such as: who created the creator--in other words--where does the transcendent being come from? And how can we posit a true beginning? People with this type of mental disposition look elsewhere for explanations.
Lighting the Way

The whole purpose of religion is to facilitate love and compassion, patience, tolerance, humility, forgiveness.

Suppose... you try to convert someone from another religion to the Buddhist religion, and you argue with them trying to convince them of the inferiority of their position. And suppose you do not succeed, suppose they do not become Buddhist. On the one hand, you have failed in your task, and on the other hand, you may have weakened the trust they have in their own religion, so that they may come to doubt their own faith. What have you accomplished by all this? It is of no use. When we come into contact with the followers of different religions, we should not argue. Instead, we should advise them to follow their own beliefs as sincerely and as truthfully as possible. For if they do so, they will no doubt reap certain benefits. Of this there is no doubt. Even in the immediate future, they will be able to achieve more happiness and more satisfaction.
...When I meet the followers of different religions, I always praise them, for it is enough, it is sufficient, that they are following the moral teachings that are emphasized in every religion. It is enough, as I mentioned earlier, that they are trying to become better human beings. This in itself is very good and worthy of praise.
Answers: Discussions with Western Buddhists

...for the Christian practitioner, the Creator and the acceptance of the Creator as almighty, is a very important factor within that tradition in order to develop self-discipline, compassion, or forgiveness and to increase them in one's intimate relationship with God. That's something very essential. In addition, when God is seen as absolute and almighty, the concept that everything is relative becomes a little bit difficult. However, if one's understanding of God is in terms of an ultimate nature of reality or ultimate truth, then it is possible to have a kind of unified approach.
...As to one's personal religion, I think this must be based on one's own mental disposition.... Generally speaking, I think it is better to practice according to your own traditional background, and certainly you can use some of the Buddhist techniques. Without accepting rebirth theory or the complicated philosophy, simply use certain techniques to increase your power of patience and compassion, forgiveness, and things like that.
Healing Anger: The Power of Patience from a Buddhist Perspective

Actually, we are all part of the community of humanity. If humanity is happy, has a successful life, a happy future, automatically, I will benefit. If humanity suffers, I too will suffer. Humanity is like one body, and we are part of that body. Once you realize this, once you cultivate this kind of attitude, you can bring about a change in your way of thinking. A sense of caring, commitment, discipline, oneness with humanity--these are very relevant in today's world. I call this secular ethics, and this is the first level to counter negative emotions.
The second level in this connection is taught by all major religious traditions, whether Christian or Muslim or Jewish or Hindu. They all carry the message of love, compassion, forgiveness, tolerance, contentment, and discipline. These are countermeasures for negative emotions. When anger is about to surface, when hatred is about to flare up, think of tolerance. It is important to stop any mental dissatisfaction when we feel it because it leads to anger and hatred.
Patience is the countermeasure for mental dissatisfaction. Greed and its self-centeredness bring unhappiness, and also destruction of the environment, exploitation of others, and increases the gap between the rich and the poor. The countermeasure is contentment. So practicing contentment is useful in our daily lives.
...All religious traditions talk about methods of compassion and forgiveness. If we accept religion, we should take the religious methods seriously and sincerely and use them in our daily lives. Then, a meaningful life can develop.
Many Ways to Nirvana: Reflections and Advice on Right Living

If we view the world's religions from the widest possible viewpoint and examine their ultimate goal, we find that all of the major world religions, whether Christianity or Islam, Hinduism or Buddhism, are dedicated to the achievement of permanent human happiness. They are all directed toward that goal. All religions emphasize the fact that the true follower must be honest and gentle, in other words, that a truly religious person must always strive to be a better human being. To this end, the different world religions teach different doctrines which will help transform the person. In this regard, all religions are the same, there is no conflict. This is something we must emphasize. We must consider the question of religious diversity from this viewpoint. And when we do, we find no conflict.
...It is a wonderful thing to have variety. It is an expression of individuality; it is a personal thing. Likewise, the variety of the different world religious philosophies is a very useful and beautiful thing.
Answers: Discussions with Western Buddhists