Modifiers of the predicate:

Direct object, freedom.

Modifiers of direct object:

Indirect object, class.

Modifiers of indirect object:

Complete predicate, would give the working class of the world, now, in our day, the freedom which they seek.

Analyze the dependent clause, which they seek, just as a principal clause is analyzed. They is the simple subject, seek is the simple predicate, which is the direct object. The complete predicate is seek which.