Thank you so much for posing this question! I found this to be helpful:

Matthew 16:19 Amplified Bible (AMP)

19 I will give you the keys (authority) of the kingdom of heaven; and whatever you bind [forbid, declare to be improper and unlawful] on earth [a]will have [already] been bound in heaven, and whatever you loose [permit, declare lawful] on earth [b]will have [already] been loosed in heaven.”

Here is an excerpt from Matthew Henry’s commentary that I found elucidating:

“Now the keys of the kingdom of heaven are,

(1.) The key of doctrine, called the key of knowledge. “Your business shall be to explain to the world the will of God, both as to truth and duty; and for this you shall have your commissions, credentials, and full instructions to bind and loose:” these, in the common speech of the Jews, at that time, signified to prohibit and permit; to teach or declare a thing to be unlawful was to bind; to be lawful, was to loose. Now the apostles had an extraordinary power of this kind; some things forbidden by the law of Moses were now to be allowed, as the eating of such and such meats; some things allowed there were now to be forbidden, as divorce; and the apostles were empowered to declare this to the world, and men might take it upon their words. When Peter was first taught himself, and then taught others, to call nothing common or unclean, this power was exercised. There is also an ordinary power hereby conveyed to all ministers, to preach the gospel as appointed officers; to tell people, in God’s name, and according to the scriptures, what is good, and what the Lord requires of them: and they who declare the whole counsel of God, use these keys well, Acts 20:27.

Some make the giving of the keys to allude to the custom of the Jews in creating a doctor of the law, which was to put into his hand the keys of the chest where the book of the law was kept, denoting his being authorized to take and read it; and the binding and loosing, to allude to the fashion about their books, which were in rolls; they shut them by binding them up with a string, which they untied when they opened them. Christ gives his apostles power to shut or open the book of the gospel to people, as the case required. See the exercise of this power, Acts 13:46; 18:6. When ministers preach pardon and peace to the penitent, wrath and the curse to the impenitent, in Christ’s name, they act then pursuant to this authority of binding and loosing.”

How liberating is the Christ, Truth! It must have been awesome to see such a departure from all the materially binding rules of the Jewish traditions, into the simply beautiful Gospel of Christ–God’s laws of heaven on earth.