Can you equip Last Rites if you don't have two units?

To equip Last Rites, you must be able to pay its full cost, which includes recycling two cards from your trash.

According to RiftJudge FAQ #8181:

"Ruling: No, you cannot equip Last Rites if you don't have two cards in your trash to recycle. Recycling two cards from your trash is part of the cost of equipping it, and costs must be paid in full to take an action."

The requirement for Last Rites is specifically to have two cards in your trash to recycle as part of the equip cost, not necessarily units. If you cannot pay that cost in full, you cannot activate the Equip ability.