Old & New
Heb 8:4-5 For if the High Priest (who is settled at the right hand of the throne of the Majesty on high) were on earth (were here), he should not be a high priest, because there are already high priests that offer gifts according to the Torah; who serve as a copy and shadow of things in heaven, as was said to Moses when he was about to make the Tent: for, “Look”, says the Torah, “that thou make them after their pattern, which was shown thee in the mountain” (Exo 25:40).
Heb 8:6 But now Yeshua has received a different priestly function, by how much also he is the mediator of a better covenant (a more advantageous and useful covenant that reflects restoring the high-priesthood after the Order of the Melchisedec, Heb 7:12-14,21-22), which was established on more advantageous and useful promises (the Greek word for "established" is nomotheteo, which means enacted by law, i.e. by the Torah).
Heb 8:7-12 Because if the first high-priesthood (Heb 7:21-28) had been without fault, then should no place have been sought for the second (Heb 8:1). For example, finding fault with them to whom it said in Jer 31:31-34, “Behold, the days come, saith YHVH, when I will cut a new covenant with the House of Israel and with the House of Judah. Not like the covenant that I cut with their fathers in the day when I took them by the hand to lead them out of the land of Egypt; a covenant they rendered null and void (Psa 119:126; Isa 24:5) even though I had married them, saith YHVH. Except in this covenant, that I will cut with the House of Israel (the House of Judah is not mentioned because they had not been divorced, Jer 3:8 & Hos 1:6-7; 2:1-23) after those days saith YHVH (after rebuilding their City and Temple, and planting them in their own Land, Jer 31:28; Zec 6:12-13), I will put my Torah in their inner part, even write it in their heart; and I will be their Elohim, and they shall be Ammi ("My People". Hos 2:23); and they shall not teach every man his neighbor, and every man his brother, saying, 'Know YHVH' ("return to an intimate covenantal relationship with YHVH"); for all shall know me, from the youngest to the eldest. For I will be merciful toward the House of Israel’s unrighteousness; and their sins, even their Torah-less-ness, will I remember no more”.
Heb 8:13 As this illustration shows, new has made that which came first, old. And whatever is becoming old is about to be abrogated and obsolescent.