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Poor in spirit = meek
Therefore, using parallelistic equivalence of phrase and Old Testament
language context we can see that 'poor in spirit' does not refer to
material poverty as Luke 6:20 taken in isolation might suggest. Rather,
it refers to being 'meek' or 'humble'. This is relevant because another
passage used by Jesus to describe his ministry is Isaiah 61:1ff., this
refers to the Spirit's anointing to preach the gospel to the poor, or
so it is usually translated. However, the Hebrew word in Isaiah is
again 'meek' and not 'poor'. Thus, it is not material poverty but
spiritual humility which is most open to hear the gospel. God shows no
partiality to rich or poor.