The Davidic covenant is the covenant where God promised Israel that; the Kingdom of King David will never lack a man to rule as a king on king David’s throne.

2 Chronicles 7:18:

then I will establish the throne of your kingdom, as I covenanted with David your father, saying, ‘You shall not fail to have a man as ruler in Israel.’

Isaiah 9:7: Justice, righteousness & God’s judgement against the wicked will be established through the Davidic covenant:

Of the increase of His government and peace There will be no end, Upon the throne of David and over His kingdom, To order it and establish it with judgment and justice From that time forward, even forever.

The zeal of the Lord of hosts will perform this.

Jeremiah 33:14-16 (NKJV)

14 ‘Behold, the days are coming,’ says the Lord, ‘that I will perform that good thing which I have promised to the house of Israel and to the house of Judah:

15 ‘In those days and at that time I will cause to grow up to David A Branch of righteousness;
He shall execute judgment and righteousness in the earth.

16 In those days Judah will be saved, And Jerusalem will dwell safely. And this is the name by which she will be called:

THE LORD OUR RIGHTEOUSNESS

Revelation 3:7 (NKJV)

The Faithful Church
7 “And to the angel of the church in Philadelphia write,

‘These things says He who is holy, He who is true, “He who has the key of David, He who opens and no one shuts, and shuts and no one opens…

8 “I know your works. See, I have set before you an open door, and no one can shut it; for you have a little strength, have kept My word, and have not denied My name.

9 Indeed I will make those of the synagogue of Satan, who say they are Jews and are not, but lie—indeed I will make them come and worship before your feet, and to know that I have loved you.

Find out more about the kingdom of king David in scriptures