an idol
Examples
Proof is an idol before whom the pure mathematician tortures himself.
A God who let us prove his existence would be an idol.
Verily, we know not what an evil it is to indulge ourselves, and to make an idol of our will.
A champion owes everybody something. He can never pay back for all the help he got, for making him an idol.
He who makes an idol of his interest makes a martyr of his integrity.
A drunkard at prayer is regarded as an idol worshipper.