Check ‘dietakse’ from ‘diatassoh’ and ‘tais ekklehsiais’. It wasn’t an “~order~” but “an arrangement I (Paul) made WITH the churches” ---not ordered TO, any churches—, there’s no Accusative of any direct object.
One can lose the message by going back to the root word when they do not like the message as it is plainly written.
I understand that it is an "arrangement" in regards for the collection of the saints, but it is an order to take a portion from the bounty collected for the church and take that portion aside for the ministry to the saints to "avoid" having a special collection for the saints when they come. That way the church has it ready beforehand for Paul and any other minister in the field because they have been regularly taking a portion from the bounty collected for the saints that minister. The order is to avoid having a special collection when Paul or any ministering saint comes.
Therefore Paul announced this arrangement, and explained it after he had finished his sermon recorded in chapter 15 as its closing words to the implied attending audience at the occasion of his sermon---, to the effect . . .
If you are thinking that Paul is reading this epistle himself originally instead of writing it, that is not a valid.
The beginning of the epistle
1 Corinthians 1:1 Paul called to be an apostle of Jesus Christ through the will of God, and Sosthenes our brother, 2 Unto the church of God which is at Corinth,....
And towards the closing of the epistle;
1 Corinthians 16:1Now concerning the collection for the saints, as I have given order to the churches of Galatia, even so do ye. 2 Upon the first day of the week let every one of you lay by him in store, as God hath prospered him, that
there be no gatherings when I come. 3 And when I come, whomsoever ye shall approve by your letters, them will I send to bring your liberality unto Jerusalem. 4 And if it be meet that I go also, they shall go with me.
5 Now I will come unto you, when I shall pass through Macedonia: for I do pass through Macedonia. 6 And it may be that I will abide, yea, and winter with you, that ye may bring me on my journey whithersoever I go. 7 For I will not see you now by the way; but I trust to tarry a while with you, if the Lord permit. 8 But I will tarry at Ephesus until Pentecost.
That does not read as if Paul was there at Corinth giving this epistle verbally.
“Please [tomorrow], on the First Day of the week, each one of you, WHEN BY YOURSELF ON YOUR OWN, LET HIM, put aside, saving whatsoever he might be able to, so that WHENEVER I come [Future Present, ‘elthoh’], you won’t have to grab together / collect (whatever).”
Paul said nothing like that he would come for the collection on the First Day. He said nothing to the churches he had preached to in the past or on the day before ---to no congregations in Galatia or wherever, that he would come for the collection on the First Day. He gave absolutely NO “~order~” to the effect and even less, introduced an “~ordinance~” to the effect all church collections should be made on the First Day of the week.
You have to ask yourself if you are wanting those inserted words to mean that or not, or whether this thinking is due to whatever doctrinal teaching you are under for wherever you are getting your schooling at, because that cannot be the message Paul is giving in the epistle.
Do discern that with Him.