Is it permissible for someone who wishes to fast on alternate days, while maintaining the fast on Mondays and Thursdays, to establish fasting on Wednesdays so that their fasting coincides with Mondays and Thursdays?

The best of fasting is the fasting of David, as he used to fast one day and break his fast one day, which is affirmed in the agreed-upon Hadith. And whoever wishes to combine the fasting of David with fasting on Mondays and Thursdays has attained a great deal of good, as it is reported that deeds are presented on Mondays and Thursdays, and the Prophet, peace and blessings be upon him, loved that his deeds be presented while he was fasting. Therefore, there is no harm in combining these acts of worship; rather, it is a hastening to good deeds.