The first part of the beatitude describes the quality to be found in believers. The latter part is the promise of spiritual benefit to the believer. The believer is to look to the promise past what they see with their eyes (Heb 11:39 -40). This is how the saints of the old testament responded to God. I think Jesus posed these in the form of a paradox because He wanted us to really think and consider them instead of quickly digesting them and moving on. Additionally, they are worded in such a way that one can never claim these qualities. In fact, to assess one's self with these attributes would be a negation of being poor in spirit which is the first listed possibly being the most important.
One facet of the paradox is that these qualities are not behaviours. We cannot own these qualities by simply "doing" them, they must be inherent within our character. The Spirit reveals all truth and righteousness to us as the Word cleanses us forming the fruit of the Spirit supernaturally.