Neither Banishing Light nor Oblivion Ring can return a commander from the command zone to the battlefield.

In the Commander guidelines, rule 903.9a says

If a commander is in a graveyard or in exile and that object was put into that zone for the reason that final time state-based actions had been checked, its proprietor might put it into the command zone. This is a state-based motion. See rule 704.

So, after the power on Banishing Light or Oblivion Ring finishes resolving, this state-based motion strikes the commander once more from exile to the command zone. At that time, the enchantment loses monitor of the cardboard, and may’t convey it again later.

This is a change from earlier guidelines, which allowed the commander to maneuver to the command zone as a substitute of the graveyard or exile as a substitute impact. Under these guidelines Banishing Light may return the commander from the command zone to the battlefield, however Oblivion Ring couldn’t try this.

The fundamental purpose that it labored that manner is rule 610.3:

Some one-shot results trigger an object to vary zones “until” a specified occasion happens. A second one-shot impact is created instantly after the desired occasion. This second one-shot impact returns the article to its earlier zone.

Banishing Light’s impact is certainly one of these. The essential factor to notice is that returning the article to its earlier zone doesn’t rely upon which zone it initially moved to.

Oblivion Ring, then again, has two separate talents, that are referred to as linked talents. Rule 607.2a describes how this sort of linked means works:

If an object has an activated or triggered means printed on it that instructs a participant to exile a number of playing cards and a capability printed on it that refers both to “the exiled cards” or to playing cards “exiled with [this object],” these talents are linked. The second means refers solely to playing cards within the exile zone that had been put there on account of an instruction to exile them within the first means.

Because Oblivion Ring’s second means refers to “the exiled card”, it could solely discover playing cards which are truly within the exile zone when it resolves.