Here are some more sources for you to ponder. They all say that bodies at equilibrium radiate equal energy toward each other.
http://spie.org/publications/optipe...t/tt48/tt48_154_kirchhoffs_law_and_emissivity
Gustav Robert Kirchhoff (1824–1887) stated in 1860 that “at thermal equilibrium, the power
radiated by an object must be equal to the power
absorbed.”
https://pediaview.com/openpedia/Radiative_equilibrium
In physics, radiative equilibrium is the condition where a steady state system is in dynamic equilibrium, with equal incoming and outgoing radiative heat flux
http://www.bing.com/knows/search?q=thermal equilibrium&mkt=zh-cn
One form of thermal equilibrium is radiative exchange equilibrium. Two bodies, each with its own uniform temperature, in solely radiative connection, no matter how far apart, or what partially obstructive, reflective, or refractive, obstacles lie in their path of radiative exchange, not moving relative to one another, will exchange thermal radiation, in net the hotter transferring energy to the cooler, and will exchange equal and opposite amounts just when they are at the same temperature.
http://everything.explained.today/Kirchhoff's_law_of_thermal_radiation/
Kirchhoff's law is that for an arbitrary body emitting and absorbing thermal radiation in thermodynamic equilibrium, the emissivity is equal to the absorptivity.
http://bado-shanai.net/Map of Physics/mopKirchhoffslaw.htm
Imagine a large body that has a deep cavity dug into it. Imagine further that we keep that body at some absolute temperature T and that we have put a small body at a different temperature into the cavity. If the small body has the higher temperature, then
it will radiate heat faster than it absorbs heat so that there will be a net flow of heat from the hotter body to the colder body. Eventually the system will come to thermal equilibrium; that is, both bodies will have the same temperature and
the small body will emit heat as fast as it absorbs heat.
Albert Einstein: "... Even in thermal equilibrium, transitions associated with the absorption and emission of photons are occurring continuously... "
This is what Max Planck said in 1914.
http://www.gutenberg.org/files/40030/40030-pdf.pdf
Page 31: The energy emitted and the energy absorbed in the state of thermodynamic equilibrium are equal, not only for the entire radiation of the whole spectrum, but also for each monochromatic radiation.
Page 50: "...it is evident that, when thermodynamic equilibrium exists, any two bodies or elements of bodies selected at random
exchange by radiationequal amounts of heat with each other..."