God created this world and everything in it as His Kingdom and gave Adam & Eve complete dominion over it. But through deception the devil made them commit sin and wrested control of the world. God decided to send His only son to die and gave the life of Jesus as one time payment for redemption from sin and get His Kingdom back. Jesus became the propitiation for all sin, including yours and mine, and did His part by giving up His life on the cross because there is no redemption without the shedding of the blood.

For by grace you have been saved through faith, and that not of yourselves; it is the gift of God, not of works, lest anyone should boast.” – Ephesians 2:4-9
As we live this earthly life and the needs burden us the question that arises in our minds “What is our role now and how do we participate” The Bible instructs us in Matthew 6:33 to “Seek first the Kingdom of God and His righteousness, and all these things will be added to you.” How do we seek the kingdom of God? Jesus said, “I tell you the truth, no one can see the kingdom of God unless he is born again.” -John 3:3 “I tell you the truth, no one can enter the kingdom of God unless he is born of water and the Spirit. Flesh gives birth to flesh, but the Spirit gives birth to spirit”. – John 3:5,6. We are born into this physical kingdom and got to be born again into the Spiritual Kingdom by accepting that Jesus Christ redeemed you from sin and death on the cross and He is alive to come and receive you unto Him. This we do with faith in God.
Kingdom of God
All of us believers are in the Kingdom of God by God’s grace and through our faith in Jesus Christ. We do not belong to the world and flesh; we belong to God and Holy Spirit. Everybody in the Kingdom is a spiritual being and therefore we should walk in spirit. Bring the Kingdom of God into our life by keeping our mind on the things above; even though we are doing physical things. Bring others into the Kingdom of God by giving the gospel of grace to them and be a living witness to them.
His Righteousness
We are made righteous not by who we are or what we have done, but by what He has done for us. It is His grace and through our faith in the finished work; by shedding of the blood of Jesus on the cross as a propitiation for our sins that we are made righteous. However much we may try to be clean and holy we still fall short of the qualifying standards that God has set to be considered Holy i.e., “all have fallen short of the glory of God” – Romans 3:20-25 . This is the kind of righteousness God is talking about. Righteousness that comes from God and not just by keeping the Law of Moses. It is made available as a free gift from God for those of us who are ready to confess our sins to Him and accept His sacrifice for our sins. Repent, seek His forgiveness, accept Jesus as your Lord & Saviour and claim your free gift of salvation.