Matthew 5:3 “Blessed are the poor in spirit, for theirs is the kingdom of heaven.” ESV
What does it mean to be poor in spirit? Does it mean that we are always putting ourselves down and believing that we are little worth? That is not what Jesus meant when He spoke of spiritual poverty. To be poor in spirit is to recognize that we have nothing in ourselves to offer to God in order to merit His forgiveness, and that we are completely dependent upon His mercy and grace. Perhaps this parable best explains it.
Luke 18:10 “Two men went up into the temple to pray, one a Pharisee and the other a tax collector. 11 The Pharisee, standing by himself, prayed a thus: ‘God, I thank you that I am not like other men, extortioners, unjust, adulterers, or even like this tax collector. 12 I fast twice a week; I give tithes of all that I get.’
13 But the tax collector, standing far off, would not even lift up his eyes to heaven, but beat his breast, saying, ‘God, be merciful to me, a sinner!’
Consider the contrast between these two men. The Pharisee boasted about his personal goodness. “God, I deserve to go to heaven because I have done these good things.” Yet, the tax collector would not so much as even lift his eyes toward heaven, but instead pleaded with God for mercy. How did God respond to these two different men?
Luke 18:14 I tell you, this man went down to his house justified, rather than the other. For everyone who exalts himself will be humbled, but the one who humbles himself will be exalted.”
God rejected the Pharisee because of his self-sufficiency. On other occasions Jesus declared that only the sick can receive healing  and only the blind can be given sight.  As long as we believe that we are good enough to earn God’s favor, God cannot help us.
In contrast, God was pleased with the brokenness of the tax collector and declared him to be justified.
Those who are poor in spirit realize that they are sinful and that they have nothing to offer to God that will satisfy His need for justice. They are completely dependent upon God to be merciful. Jesus said that the poor in spirit will not only receive God’s forgiveness, they will also receive heaven as their reward.
 Matthew 9:12
 John 9:39 NLT