Jeremiah 14:12
When they fast, I will not hear their cry; and when they offer burnt offering and an oblation, I will not accept them: but I will consume them by the sword, and by the famine, and by the pestilence. When they fast, I will not hear their cry; and when they offer burnt offering and an oblation, I will not accept them: but I will consume them by the sword, and by the famine, and by the pestilence.
Jeremiah 14:12 is addressed to a people who have forsaken God and turned to follow their own corrupt ways. When they have thus turned away and are rejected, their fasting will not cause Him to hear their cry, and their burnt offerings and oblations will not be accepted by Him. In that condition outward worship cannot secure His favor nor turn aside or avert His judgment. Instead He will consume them by the sword, and by the famine, and by the pestilence.
In this sense the verse applies to a nation's present calamity for forgetting and forsaking God and for breaking His law and covenant. That national breach of the covenant includes despising the Sabbath. The same sword, famine, and pestilence, with great confusion in the land, mark the judgments at the commencement of the time of trouble. In that time the wicked will blame God's people who proclaim the Sabbath for bringing the judgments upon them. They will conspire to destroy them and to rid the earth of them, believing that their deaths will stop the evils and end the calamities.