In 2 Corinthians 3.6 Paul defines aspects of the New Covenant which are different from the Mosaic Covenant of the “letter”: who made us adequate to be servants of a new covenant not based on the letter but on the Spirit, for the letter kills, but the Spirit gives life. (NET) Here Paul describes one of the Law’s functions: “to kill”. The sense of what Paul is saying is that the commandments of the Old Covenant exposed our deficiency to keep those commandments perfectly and thus the Law of the Sacrifice was necessary to atone for that sin by bringing a substitute for the offender, a sin offering. The person would place their hands on the animal and confess their sin then the priest would offer it on the altar after it had its throat cut.
The good news of the New Covenant is that Christ has atoned for sin once for all time and the Spirit is given on that basis to those who turn to Christ in faith. This New Covenant was promised in a detailed manner especially in Jer. 31.31-34 toward the end of Israel’s Theocratic Kingdom:
“Indeed, a time is coming,” says the Lord, “when I will make a new covenant with the people of Israel and Judah. It will not be like the old covenant that I made with their ancestors when I delivered them from Egypt. For they violated that covenant, even though I was like a faithful husband to them,” says the Lord. “But I will make a new covenant with the whole nation of Israel after I plant them back in the land,” says the Lord. “I will put my law within them and write it on their hearts and minds. I will be their God and they will be my people. “People will no longer need to teach their neighbors and relatives to know me. For all of them, from the least important to the most important, will know me,” says the Lord. “For I will forgive their sin and will no longer call to mind the wrong they have done.” (NET)
Before we look at 1John, a few notes on the time frame of when this New Covenant was to happen: “after I plant them in the land” (“after these things”-Heb.). Jeremiah had long prophesied that Judah would be exiled but then allowed to return after 70 years (605-535 BCE). Also, Dt. 30.1-6 promises “heart circumcision” after the exile due to breaking the Old Covenant. Additionally, Ezekiel 11.14-20 promises a removal of the stony heart to be replaced with the fleshly heart after the restoration from the Babylonian Captivity. Again, Ezekiel 36.24-27 promises after Israel returns from captivity that 1. Cleansing 2. New heart and spirit 3. Fleshly heart 4. The Spirit enabling to keep God’s regulations.
The last OT prophet Malachi promised the “Messenger of The Covenant” who will be the Lord Himself: “I am about to send my messenger, who will clear the way before me. Indeed, the Lord you are seeking will suddenly come to his temple, and the messenger of the covenant, whom you long for, is certainly coming,” says the Lord who rules over all. (Malachi 3.1 NET) John the Baptist was the first messenger who cleared the way for the Messenger of the Covenant who was Jesus who was longed for to pay redemption’s price for all of humanity.
Without specifically mentioning The New Covenant, the Apostle John in his first epistle described the new relationship (covenant) that believers in Jesus enjoy. 1 John 2.20 contrasts those who have not left the faith of verse 19 as having the anointing (Holy Spirit) and that they all “know”: Nevertheless you have an anointing from the Holy One, and you all know. While true that some manuscripts have the accusative form (in the Koine Greek) and additional “things”, this certainly doesn’t make sense. Even the apostles in the first century were not cognizant of many aspects. Also, it would be normal for the scribes hearing the epistle read would naturally add “things” to give the verb its object when in reality the clause ends with “know”. It is abundantly clear to many scholars that this is a reference to Jer. 31.34 where they (believers) would all “know” the Lord. Therefore, the Greek nominative case (subjective-“you all know”) is preferred over the accusative case (direct object-“you know all things”).
1 John 2.27 again mentions this anointing as a person (the Holy Spirit) who teaches the New Covenant believer to abide in Christ: Now as for you, the anointing that you received from him resides in you, and you have no need for anyone to teach you. But as his anointing teaches you about all things, it is true and is not a lie. Just as it has taught you, you reside in him. (NET)
“Chrisma” is the word in Greek which referred to the anointing oil such as what the High Priests would be anointed with in the OT. This OT oil was a symbol for the NT Holy Spirit promised in the New Covenant.
An aspect of “the times of the Lord” (Lev.23) was the festivals which every male Israelite was to attend. The Passover was fulfilled in Christ’s sacrifice: Your boasting is not good. Don’t you know that a little yeast affects the whole batch of dough? Clean out the old yeast so that you may be a new batch of dough—you are, in fact, without yeast. For Christ, our Passover lamb, has been sacrificed. So then, let us celebrate the festival, not with the old yeast, the yeast of vice and evil, but with the bread without yeast, the bread of sincerity and truth. (1Cor. 5.6-8 NET) All three synoptic Gospels (Mt., Mk., Lk.) mention Christ at the Last Supper referring to the cup of wine as His symbolic blood of the Covenant which was expected (New). Christ would shed His own blood (and so enacting The New Covenant) in our stead accomplishing redemption. The Last Supper was during the time of the first lamb of Passover (Christ’s crucifixion occurred at the ‘second lamb’ is my view).
The second festival of the “times of the Lord” all male Israelites were to attend was Shavuot or in Greek, Pentecost (50 days). Jesus instructed His disciples to wait for “the promise from the Father” (“another advocate”) which happened when the Spirit descended on the 120 believers assembled together for the festival Shavuot. This is the anointing which John speaks about in his epistle: the Holy Spirit’s indwelling all faithful to Christ. It is how Christians “know” the Lord.