For your employer to have made a counter offer to you, I assume you must have handed in your resignation as you had accepted a new position. In my experience, supported by research, the reason people resign is not just about money. After a counter offer has been accepted, the average time before someone hands their resignation in for a second time is about eight months. Many factors make up our working lives, such as learning and career opportunities, our colleagues, working environments and, of course, the remuneration we are paid. I would imagine your original reasons for wanting to leave would not have been resolved just by the extra remuneration.
You need to have a very detailed discussion with your manager (or HR), which is something you should have attempted prior to starting your job search. You obviously have a skill set that is valuable to your employer, but it sounds as though you both want different things. You need to ask yourself, 'Why am I worth more after I resign, rather than before?' The statistics to support you staying aren't on your side; there still is a very high chance you will leave.
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