Welcoming the undocumented resident refugee into the life of the polis is a challenge for some communities and a moral imperative for others. This books provides a Christian ethic for church leaders, congregants, and their churches to discern a way of welcoming their neighbors who are refugees residing in the US without authorization. Grounded in political theology and the Presbyterian-Reformed faith tradition, the ethical debates presented here and the legal overview of US immigration and alienage laws applicable to the undocumented resident lead to practices of worship, witness, and welcome for churches that can be tailored to different contexts. When Jesus challenged the sharp lawyer to love his neighbor as himself, the lawyer asked Jesus: ""who is my neighbor?"" Jesus responded by telling him the parable of the Good Samaritan. Then Jesus asked the lawyer: ""who was a neighbor to the man who fell into the hands of the robbers?"" And the crestfallen lawyer answered: ""the one who showed him mercy."" Jesus told him ""to go and do likewise."" This book assists faith communities to find mercy for those undocumented refugee neighbors who many would condemn. It points a path towards doing the ""likewise"" of mercy in ethically defensible ways.