Whoever vs. Whomever
To determine whether to use whoever or whomever, the he/him rule in the Who/Whom section applies:
he = whoever
him = whomever
Rule 1. The presence of whoever or whomever indicates a dependent clause. Use whoever or whomever to agree with the verb in that dependent clause, regardless of the rest of the sentence.
Example: Give it to whoever asks for it first.- Отдай это тому, кто первый попросит.
He asks for it first. Therefore, whoever is correct.
Example: We will hire whomever you recommend.- Мы наймем того, кого Вы порекомендуете.
You recommend him. Therefore, whomever is correct.