From Apocalypse Explained ~ Emanuel Swedenborg
For Thou wast slain, and hast redeemed us to God by Thy blood ... Rev 5:9
... the signification of "thou didst redeem us to God in Thy blood," as being that He conjoined us to the Divine by the acknowledgment of Him, and by the reception of  Divine truth from Him; for "to redeem" signifies to liberate from hell, and  thereby to appropriate men to Himself, and thus enjoin them to the Divine .... The "blood of the Lord" signifies  Divine truth proceeding from Him; and because man by the reception of Divine  truth from the Lord is liberated from hell and conjoined to Him, therefore "Thou  didst redeem us to God in Thy blood" signifies conjunction with the Divine by  the reception of the Divine truth from the Lord.
...the angels who are with men have no perception of these things according to that  sense [of the letter], but according to the spiritual sense, for they are spiritual and  therefore think spiritually and not naturally. To angels, "redeeming man in His  blood" means liberating man from hell, and thus claiming and conjoining man to  Himself by the acknowledgment of Him, and by the reception of Divine truth from  Him. Moreover, the church may know that this is so; for it may know that no one  is conjoined to the Divine by blood, but by the reception of the Divine truth,  and the application of it to the life.
Liberation from hell by the Lord  was accomplished by His assuming the Human, and through it subjugating the  hells, and reducing to order all things in the heavens, which could have been  done in no way except by the Human; for the Divine operates from firsts through  ultimates, thus from Himself through the things that are from Himself in  ultimates, which are in the Human. This is the operation of Divine power in  heaven and in the world.
Liberation  from hell by the Lord was also accomplished by His glorifying His Human, that  is, making it Divine; for thus and not otherwise could He hold the hells in  subjection forever; and as the subjugation of the hells and the glorification of  His Human was accomplished by means of temptations admitted into his Human, His  passion of the cross was His last temptation and complete victory. That "He bore  the sins of all" signifies that He admitted into Himself all the hells when He  was tempted, for from the hells all sins or evils ascend, and enter into man and  are in him; therefore the Lord's "bearing sins" signifies that He admitted the  hells into Himself when tempted; and His "taking away sins" means that He  subjugated the hells, in order that evils may no more rise up from them, with  those who acknowledge the Lord and receive Him, that is, who receive in faith  and life the Divine truth proceeding from Him, and who are thus conjoined to the  Lord.
It was said that "Thou didst redeem us to God in Thy blood" signifies  conjunction with the Divine by the acknowledgment of the Lord, and the reception  of Divine truth from Him; and as the church is founded on this, I will state  briefly how conjunction is thereby effected:
The primary thing is to  acknowledge the Lord, to acknowledge His Divine in the Human, and His  omnipotence to save the human race; for by that acknowledgment man is conjoined  to the Divine, since there is no Divine except in Him; for the Father is there;  for the Father is in Him, and He in the Father, as the Lord Himself teaches;  consequently they who look to another Divine near Him, or at His side, as those  are wont to do who pray to the Father to have mercy for the sake of the Son,  turn aside from the way and worship a Divine elsewhere than in Him.
Moreover, they then give no thought to the Divine of the Lord, but only to the Human, when  yet these cannot be separated; for the Divine and the Human are not two, but a  single person, conjoined like soul and body, according to the doctrine received  by the churches from the Athanasian Creed.
Therefore to acknowledge the Divine  in the Lord's Human, or the Divine Human, is the primary thing of the church, by  which there is conjunction; and because it is the primary it is also the first  thing of the church. It is because this is the first thing of the church, that  the Lord, when He was in the world, so often said to those whom He healed,  "Believest thou that I can do this?" and when they answered that they believed,  He said, "Be it done according to thy faith." This He so often said that they  might believe, in the first place, that from His Divine Human He had Divine  omnipotence, for without that belief the church could not be begun, and without  that belief they could not have been conjoined with the Divine, but must have  been separated from it, and thus would not have been able to receive anything  good from him.
Afterwards the Lord taught how they were to be saved, namely, by receiving Divine truth from Him - Truth is received when it is  applied to the life and implanted in it by doing it; therefore the Lord so often  said that they should do His words. From this it can be seen that these two  things, namely, believing in the Lord and doing His words, make one, and can by  no means be separated; for he who does not do the Lord's words does not believe  in Him; so also he who thinks that he believes in Him and does not do His words  does not believe in Him, for the Lord is in His words, that is, in His truths,  and by them He gives faith to man.
From these few things it can be known that  conjunction with the Divine is effected through the acknowledgment of the Lord  and the reception of Divine truth from Him. This, therefore, is what is  signified by "the Lamb redeeming us to God in His blood." 
(A portion of Apocalypse Explained 328:2, 4-7)