Some of my non adventist brethren quote 1John 3:22-24 and say that John is not talking about the decalogue in his epistle. But a careful reading of the entire epistle shows that John is talking about the Decalogue including the 7th day Sabbath.
Apostle Paul tells us that Love is the fulfillment of the Law. Without love we cannot fulfill the law. He also tells us that to say love thy neighbour is the summary of last six commandments in the Ten Commandments.
Rom 13:8,9 Owe no man any thing, but to love one another: for he that loveth another hath fulfilled the law.For this, Thou shalt not commit adultery, Thou shalt not kill, Thou shalt not steal, Thou shalt not bear false witness, Thou shalt not covet; and if there be any other commandment, it is briefly comprehended in this saying, namely, Thou shalt love thy neighbour as thyself.
The same thing was told by the Lawyer to the Lord as answer to his question. Luk 10:25-27 And, behold, a certain lawyer stood up, and tempted him, saying, Master, what shall I do to inherit eternal
life? He said unto him, What is written in the law? how readest thou? And he answering said, Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy strength, and with all thy mind; and thy neighbour as thyself.
The first 4 commandments in the Decalogue can be summarized into “Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy strength” and the last 6 commandments can be summmarized as “love thy neighbour as thyself”
With this in mind let us see which commandment does John refers to.
1Jn 3:22-24 And whatsoever we ask, we receive of him, because we keep his commandments, and do those things that are pleasing in his sight. And this is his commandment, That we should believe on the name of his Son Jesus Christ, and love one another, as he gave us commandment. And he that keepeth his commandments dwelleth in him, and he in him. And hereby we know that he abideth in us, by the Spirit which he hath given us.
In both verse 22,24 John uses the plural word ‘commandments’ so he not talking about only one commandment here rather more than one commandment.
From 1Jn 4:20-21 we can see that John is talking about the entire decalogue.
If a man say, I love God, and hateth his brother, he is a liar: for he that loveth not his brother whom he hath seen, how can he love God whom he hath not seen? And this commandment have we from him, That he who loveth God love his brother also.
John asks how can we love God (keep the first 4 commandments) if we do not love our neighbour (keeping last 6 commandments).
Also He writes 1Jn 5:21 Little children, keep yourselves from idols. Amen.