You need energy to separate two atoms that want to be together.
(You'd require energy to push apart these huggers - after all they want to cling together)
However when they join together and make a bond, they release energy - like heat or sparks.
(But when they join together, they'd release noise and kinetic energy.)
Reactions may be endothermic or exothermic overall as the energy required to break the bonds may be smaller or greater than the energy to make new ones.
I don't know the context of your biology, so I can't say why they may have said that.
I know that I am taught ATP -> ADP + Pi + energy. This isn't the entire reaction. It also involves water to make it, and thus bonds are also made, releasing energy.
I hope this helps in someway!