What does Matthew 5:20 mean?

Matthew 5:20 KJV
For I say unto you, That except your righteousness shall exceed [the righteousness] of the scribes and Pharisees, ye shall in no case enter into the kingdom of heaven.

Matthew 5:20 NKJV
“For I say to you, that unless your righteousness exceeds [the righteousness] of the scribes and Pharisees, you will by no means enter the kingdom of heaven.

Matthew 5:20 MKJV
For I say to you that unless your righteousness shall exceed [that] of the scribes and Pharisees, you shall in no case enter into the kingdom of Heaven.

Matthew 5:20 KJV 2000
For I say unto you, That except your righteousness shall exceed the righteousness of the scribes and Pharisees, you shall in no case enter into the kingdom of heaven.

Interlinear KJV

For /gar/ I say /lego/ unto you, /humin/ That /hoti/ except /ean me/ your /humon/ righteousness /dikaiosune/ shall exceed /perisseuo/ /pleion/ the righteousness of the scribes /grammateus/ and /kai/ Pharisees, /Pharisaios/ ye shall in no case /ou me/ enter /eiserchomai/ into /eis/ the kingdom /basileia/ of heaven. /ouranos/

Albert Barnes’ Commentary

Verse 20. Your righteousness. Your holiness, your views of the nature or righteousness, and your conduct and lives. Unless you are more holy than they are, you cannot be saved.

Shall exceed. Shall excel, or abound more. This righteousness was external, and was not real holiness. The righteousness of true Christians is seated in the heart, and is therefore genuine. Jesus means, that unless they had more real holiness of character than the scribes, they could not be saved.

The righteousness of the Scribes and Pharisees. See Barnes “Mt 3:7”.

Their righteousness consisted in outward observances of the ceremonial and traditional law. They offered sacrifices, fasted often, prayed much, were very punctilious about ablutions and tithes and the ceremonies of religion, but neglected justice, truth, purity, holiness of heart, and did not strive to be pure in their motives before God. See Mt 23:13-33.

The righteousness that Jesus required in his kingdom was purity, chastity, honesty, temperance, the fear of God, and the love of man. It is pure, eternal, teaching the motives, and making the life holy.

The Kingdom of heaven. See Mt 3:2. Shall not be a fit subject of his kingdom here, or saved in the world to come. {q} “shall exceed the righteousness” Mt 23:23-28; Php 3:9