Life after death

As a follower of Buddha I believe in sansara, a never ending cycle of death and birth which only ceases by cessation of desire. I have many friends who are of different faiths that don't believe in this. They strictly believe in one life and thereafter a judgement day where god holds accountable everyone for what they have done during there lifetime.

The point that I use to support my claim is that we are all born different, some poor some rich, some healthy some sick and so on. But they counter argue by saying that it is all God's test. If you are rich they it is either a reward or a test to check if that privilege is used live a good life and consent to the will of god. If one is poor that is also a test by god. While I have some points to counter argue I have never been able to give a convincing answer.

My intention is not to convert them or to undermine their faith in god. But it would be nice if I could rid them of some of the delusional thinking that they got going so that some day they would realize life for it really is. How can I do this?