Authority

Matthew 28:18 And Jesus came and said to them, "All authority in heaven and on earth has been given to me."

Marian exclaimed:

ALL authority in heaven and on earth? yikes! what happened to checks and balances??? ...

Yes, ALL authority because Christ Jesus is the creative Word through which everything in existence was made, the redemptive Word and the ascended, sovereign Word from which the Spirit proceeds. Checks and balances? There are none, at least not in the way we humans imagine them, as in the kind of earned justice and just desserts we like to deal in. For many people a lot of the time it's not about human dignity, need and worth but more about earning points vis-à-vis that person's behavior's effect on me! Regarding the authority of the incarnate, risen and ascended Word, we're sometimes not willing to yield to its claim, demands and authority when it dawns on us we're called to lives as crucified and resurrected people: to die and then to let ourselves be raised according to God's design rather than ours...

Jesus' authority...kinda like the law of gravity?!

Well, no, not quite, since Jesus' authority needs to be obeyed to become effective: although I'm not remotely a scientist, I think gravity's in effect here on earth no matter what we do?

Daniel 7:14

13 I was watching in the night visions,
And behold, One like the Son of Man,
Coming with the clouds of heaven!
He came to the Ancient of Days,
And they brought Him near before Him.

14 Then to Him was given dominion and glory and a kingdom,
That all peoples, nations, and languages should serve Him.
His dominion is an everlasting dominion,
Which shall not pass away,
And His kingdom the one
Which shall not be destroyed. NKJV

This passage evokes the Christus Pantocratur ascription from Revelation 11:17:

"We give Thee thanks, O Lord God, the Almighty, who art and who wast, because Thou hast taken Thy great power and hast begun to reign. ..."

But to begin answering:

And I'm still wondering about...how on earth do we obey the authority of Jesus in a corporate way? How do we obey as church? ...IS there any such thing as institutional obedience?

So much to consider! The PC(USA), says the Church is the "provisional demonstration of what God intends for humanity." (Paraphrased, but I think I've got the essence.) They don't say each individual Christian is that "provisional demonstration," but rather they're talking about all of us in our called-together and sent-out bodily corporateness, as local churches, local denominational and ecumenical ministeriums and regional judicatories, trans-national church bodies, too - such as the Lutheran World Federation and the World Communion of Reformed Churches. And this more than just touches on polity issues and questions. What polity is best where and for whom? There's such a plethora of variant answers and opinions to that question, I don't know.