Activate Ashnod's Altar by sacrificing Ancestor's Chosen.
When Ancestor's Chosen dies, Orah triggers, returning Sister Hospitaller from your graveyard to the battlefield.
When Sister Hospitaller enters, it triggers, returning Ancestor's Chosen from your graveyard to the battlefield and causing you to gain 7 life.
When Ancestor's Chosen enters, it triggers, causing you to gain 1 life for each card in your graveyard.
Activate Ashnod's Altar by sacrificing Sister Hospitaller.
When Sister Hospitaller dies, Orah triggers, allowing you to return a Cleric with mana value 5 or less from your graveyard to the battlefield.
Repeat.

Infinite ETB

Infinite LTB

Infinite colorless mana

Infinite death triggers

Infinite lifegain

Infinite lifegain triggers

Infinite recursion of some creature cards in your graveyard

Infinite sacrifice triggers

Orah, Skyclave Hierophant

Sister Hospitaller

Ancestor's Chosen

Ashnod's Altar

Tap Kiki-Jiki to create a token copy of Ancestor's Chosen with haste.
The token enters gaining you 12 life.
Pay 12 life to Treasonous Ogre to add {R}{R}{R}{R}.
Pay {1} to untap Staff of Domination and {3} and tap Staff of Domination to untap Kiki-Jiki.
Repeat.

Infinite creature tokens with haste

Kiki-Jiki, Mirror Breaker

Staff of Domination

Treasonous Ogre

Tap Kiki-Jiki to create a token copy of Ancestor's Chosen with haste.
The token enters gaining you 9 life.
Pay 9 life to Treasonous Ogre to add {R}{R}{R}.
Pay {3} to untap Kiki-Jiki.
Repeat.

Sword of the Paruns

Umbral Mantle

Combos with "Ancestor's Chosen"