Move to your draw step, drawing Approach of the Second Sun and revealing it due to God-Eternal Kefnet's ability.
Resolve God-Eternal Kefnet's trigger, copying Approach of the Second Sun and casting the copy from your hand by paying {4}{W}.
Sunbird's Invocation triggers.
In response, activate Penance by putting Approach of the Second Sun on top of your library, declining to choose a source.
Resolve the Sunbird's Invocation trigger, revealing the top seven cards of your library, casting Approach of the Second Sun without paying its mana cost, then putting the rest of the revealed cards on the bottom of your library.
Resolve Approach of the Second Sun, putting it back into your library seventh from the top and gaining you 7 life.
Resolve the remaining copy of Approach of the Second Sun.

Win the game

Approach of the Second Sun

Sunbird's Invocation

God-Eternal Kefnet

Penance

Play Azorius Chancery.
When Azorius Chancery enters the battlefield, it and Retreat to Coralhelm trigger.
Resolve the Azorius Chancery trigger, returning it from the battlefield to your hand.
Holding priority, activate Penance by putting Azorius Chancery from your hand onto the top of your library.
Resolve the Retreat to Coralhelm trigger, causing you to scry 1, ensuring to leave Azorius Chancery on top of your library.
Galadriel triggers, putting Azorius Chancery from the top of your library onto the battlefield tapped.
Repeat from step 2.

Combos with "Penance"