You have the time frame completely wrong. Heb. 8:13 is referring to the time of the PROPHET (who has just been quoted at length), not the time of the author of Hebrews.
How could the Old Law conceivably be “close to passing away” when Hebrews was WRITTEN? It was GONE when the veil in the temple was torn open.
It helps to THINK, rather than just scouting around through Scripture looking for phrases that look like convenient weapons.
No, the Prophet is not quoted there - that is indeed commentary by the author. The prophet in question is Jeremiah in 31:31. Note the context of the chapter. And note that the time Jeremiah proclaims includes Torah written on the inward parts of all men (that certainly is *not*, even to this day)- and certainly not thrown away as being old.
It was GONE when the veil in the temple was torn open.
Not ONE jot or tittle until all is fulfilled. Not only Torah, but the Prophets.
Mat 5:17 Think not that I came to destroy the law or the prophets: I came not to destroy, but to fulfil.
Mat 5:18 For verily I say unto you, Till heaven and earth pass away, one jot or one tittle shall in no wise pass away from the law, till all things be accomplished.
Mat 5:19 Whosoever therefore shall break one of these least commandments, and shall teach men so, shall be called least in the kingdom of heaven: but whosoever shall do and teach them, he shall be called great in the kingdom of heaven.
Mat 5:20 For I say unto you, that except your righteousness shall exceed the righteousness of the scribes and Pharisees, ye shall in no wise enter into the kingdom of heaven.
The Torah is not completely fulfilled. The Prophets are not completely fulfilled. Heaven and earth are still here.