Battles of Beleriand

[Tuor of Gondolin]

Excellent point by Numenorean about the importance of the dwarves,
throughout the history of Beleriand, and not just in the First Battle. Indeed,
it seems it wasn't the Sindar unwitting persecution of the Petty Dwarves but rather Thingol and the Nogrod dwarves desire for a silmaril that caused resentments only healed with Legolas and Gimli.

The Belgrod dwarves ready (and vital) assistance to Thingol against Morgoth is partially explained by their nature. As Robert Foster summarizes in The complete guide to Middle-earth:

Intended by Aule to endure the power of Melkor, Dwarves were short (four and a half to five feet tall), stocky, strong, resistant to fire, and hardier than any other race. Unswerving and proud, Dwarves could not be dominated by evil and never forgot a wrong or a debt; they went to war frequently and wielded axes.

It's interesting that Morgoth did not try an initial foray against the dwarves,
despite the description of goblins in The Hobbit as nearly as skilled as dwarves at underground tunnelling and fighting.