Thirteen times, in the book of Hebrews, the author uses an edifying, faith building Greek device. This device usually begins with the expression let us. I call it simply a let us exhortation.
In other words, when an author used this grammatical device, he/she simply exhorted someone to join in with him/her in an action. He/she could exhort one to join in and help start an action that had not yet begun.
Or he/she could exhort someone to join in an action that had begun already: namely an action that was in progress and in which the author or speaker was already engaged.
In Hebrews, both kinds were used by our author. See his Let Us Exhortation # 5 below.
Heb 4:16
Let us therefore come boldly unto the throne of grace, that we may obtain mercy, and find grace to help in time of need. (KJV)
In this passage, Let us signifies that the author is already engaged in the action of boldly coming to the throne of Grace. He is presently coming to this throne to get some things.
First, he goes there to obtain mercy. Second, he goes there to find grace to help. Third, he goes there to get the above two things in a timely fashion, when the...