New Covenant and the Visible/Invisible Church

I plan to look more into the nature of the new covenant and it's relation to the covenant of redemption. Here are some possible starting points in the teachings of Jesus concerning the kingdom of God.

Jesus' various teachings on the kingdom of God prove that, as of yet in this age, the boundaries of his kingdom are not entirely visible and clear. I'm thinking particularly of the teachings of the leaven and the mustard seeds.

But the one thing that is certain is that sinners enter into the kingdom by faith and baptism. Does that mean all visible members of the church (professing faith and undergoing baptism) are the elect people of God? No, still at this present time the sons of glory have not been revealed.

Jesus promised to his disciples at the last supper:

"just as My Father has granted Me a kingdom, I grant you that you may eat and drink at My table in My kingdom, and you will sit on thrones judging the twelve tribes of Israel." Luke 22:29-30

Literally it can be rendered, "Just as my Father has covenanted me a kingdom, so I covenant you..."

Before objecting that he is only covenanting the kingdom to the twelve disciples, recall that the kingdom glory is both here and elsewhere spoken of in terms of feasting at his table, and with a general invitation to all people. Hence the parable of the wedding feast in Matthew 22 -

"Those slaves went out into the streets and gathered together all they found, both evil and good; and the wedding hall was filled with dinner guests.

But when the king came in to look over the dinner guests, he saw a man there who was not dressed in wedding clothes, and he said to him, 'Friend, how did you come in here without wedding clothes?' And the man was speechless. Then the king said to the servants, 'Bind him hand and foot, and throw him into the outer darkness; in that place there will be weeping and gnashing of teeth.'

For many are called, but few are chosen." Matt. 22:10-14

Without the wedding garment of righteousness (justification), no one can attend this feast of the kingdom. But some will try. Sadly there will be some who may have outwardly heeded the invitation (profession of faith and baptism) but will be exposed by the king as an unrighteous and thus unworthy participant.

All this is to say that the NT definitely makes a distinction in this present age; one the hand the elect who are justified, receive full forgiveness of sins, and covenanted a kingdom glory. They are ones for whom Christ is the mediator of an eternal covenant and intercedes for all those whom he came to save by praying that their faith may not fail, and all of whom will one day feast with the king in the full glory of his eternal kingdom.

On the other hand there is a visible community where the general invitation is given to enter this kingdom by faith and baptism, a place where the Word of God is proclaimed, the hope of glory, and warnings are given against falling away from the Word which saves.