"on the first matter" is a correct and usable phrase in written English.
It is used to refer to the initial or primary topic or issue being discussed. You can use it in a sentence when introducing multiple matters or topics and want to specify which one is being addressed first. Example: "Let's discuss the budget for the upcoming fiscal year. On the first matter, we need to review the proposed allocations for each department."
The leak investigation was the first matter on the board's agenda.
On the second matter he said: "The discussion was relatively long..
No matter where you stand on the Second Amendment, no matter where you stand on guns, we have a right to hear from both of them concretely, not just in generalities – specifically what are they going to do about guns?
Regardless of whether you have one on you, the first words on the matter have to be: "Er, do you have a condom?" Not the presumptuous: "I've got a condom!" sung to the tune of: "I'm the king of the castle!" One morning I was in flagrante with a nice man I didn't know terribly well – I wouldn't have been able to spell his surname with confidence – and the need for a condom had been established.
In the meantime, Nissan has taken refundable deposits on the first 20,000 Leafs, no matter what the sticker says.
Some people may wish to avoid the embarrassment of being caught with a hickey, or the hassle of trying to cover one up, so you should never give one without sussing out your partner's feelings on the matter first.
And his shifting statements on the matter — first blaming "both sides," then condemning Nazis, then blaming the "alt-left" for provoking the Nazis — reveal a man seemingly unable to censor his darkest feelings on race, even if it means offending wide swaths of the nation and damaging his ability to execute a political agenda going forward.
But when it really mattered, on the first run in the third and final one, he put it all together.
Moreover, this is a potentially important dose confounder, as there was no knowledge of the dose provided to these patients on the first day, when it probably mattered most.
The committee deferred action on the third allegation, because that matter is being investigated by a grand jury in Texas.
