Charge!

'But would leaving this place be a good idea? Is it possible to leave and come back?' Kentucky asked. 'At the moment, we only know the first step to reach the Celestial Realm, nothing else.'

Back then, when the twins' group reached the Divinity Realm, they experienced a tribulation. With that, they managed to absorb the Celestial Laws. Light and Dark for Rean, Roan, and Kentucky. Wood and Absorption for Celis. (Chapter 2853)

According to Sister Orb, they would need to merge their laws with their absorbed Celestial Laws. Once that was done, they would comprehend the Celestial Laws. That was the first step. So, when the twins thought about Triaglia and the others who reached the Celestial Realm in this Golden Palace, they got the same idea.

From the start, they felt the Celestial Laws in the portrait, and they could also feel them around this place, even if they couldn't touch or comprehend them because of their low cultivation.