Shemiras Halashon Halachos
Hilchos Lashon Hara, Opening – positive commands (11) Someone who speaks lashon transgresses the positive command, "Fear the L-rd your G-d," which warns us to know that Hashem always observes our actions and punishes us according to the severity of our actions. Certainly, someone who abandons himself to this sin of lashon hara has neglected this positive command.
Hilchos Lashon Hara, Opening – positive commands (12) Above all, at the time one speaks lashon hara and rechilus, one transgresses the positive command of Torah study, which is an absolute positive command, and there is no limit to the reward of this command, which weighs equal to all the commands. Conversely, the punishment for neglecting it is equal to all the sins as the sages say, "The Holy One forwent the sin of idolatry, immorality, and bloodshed, but did not forgo the sin of neglect of Torah."
A person occupied in his livelihood or searching for work, will be cleared of this sin in the supernal court. But at the time he speaks lashon hara or rechilus, what benefit accrued to his livelihood from this? He also transgresses a number of negative commands that apply to someone who separates himself from the Torah.