What purpose are these patterns for? I oppose / interest myself....

Hello,

I don't know these expressions like the following sentences are for what purpose.

If anyone could clear it up I will be very grateful.
Thank you!

(1) I interested myself in this question. = I was interested in this question.
Here, in = attending on / for

(2) I opposed myself to his suggestions. = I was opposed to his suggestions.
Here, to = for the attention of