Is it legal for a pastor to receive a monthly love offering and a salary?
It's perfectly legal. It is also most probably taxable income.
In order for a love offering to be nontaxable to the recipient, it must be spontaneous in nature, not solicited, and clearly defined as a gift with no service attached.
A regular love offering every month does not fit those criteria. So, yes...a pastor could receive a monthly love offering and salary; however, they should be aware that it is all...most likely taxable income.