Monotheists preach the necessity of correct belief but disagree on which belief is correct. Some believe that Jesus is their unique savior, others that Muhammad was Allah's last prophet. Monotheist spiritual practice is prayer to a god who is believed to exist.
Buddhists teach the necessity of understanding mental states. Their spiritual practice is reflective awareness of such states. Buddhists try to see reality and mind as they are, not as interpreted according to a belief. Buddhist teaching is a formulation of meditative insights, not a divine revelation or creedal statement.
Believers interpret their experiences according to their beliefs. Evangelical Christians experience (i) conversion or salvation and (ii) suffering as a consequence of their sins. (ii) corresponds to Buddhist "karmic consequences." (i) is a conviction of oneness with ultimate reality. This conviction may be valid. As part of reality, we are ontologically one with it although psychologically alienated from it. Buddhists have two disagreements with the Christian formulation of this conviction. First, Christians personify ultimate reality. Secondly, interpreting exclusivist Evangelical passages literally, they deny this oneness to anyone else.
Buddhist understanding is based on meditative insight, not on statements in a book. Buddhists aim to live mindfully and to die without unresolved karma. There are teachings about where unresolved karma goes after death. I suggest that rebirth teaching is a re-interpretation of pre-Buddhist belief in reincarnation. If belief in God and Christ were removed from Christianity, then it would cease to be Christianity whereas, if belief in rebirth is removed from Buddhism, then the Four Noble Truths, karma and meditation remain. We can be mindful until the moment of death and agnostic about what, if anything, occurs after it.
Does meditation confirm rebirth? Usually, it shows us our present state and our past in this life. Can memories of previous lives, if they occur, be differentiated from imaginings of previous lives? We must ask such questions and cannot answer them yet. Science, philosophy and meditation bring us to the threshold of whatever answers may be. Religious believers leap across the threshold into different virtual realities.
Urgent social problems and evidence that consciousness is materially based entail that we should de-prioritize speculation about survival. Therefore, I advocate the practice not of prayer but of meditation and of revolution.