How to Obtain

The in-game "How To Get" says this:

“	Eliminate an Apostle without the squad failing any skill combo of Shield of Trust, Celestial Spike, and Judgment Blade.	„

However, I learned this skill without doing any raids or whatever, right after completing G19#Answers from Above?

Did you do the combo in the finale against the two Girgashiy?

What exactly is the combo? If the finale counts for it, then I probably did so unknowingly.

1. Girgashiy uses Mineral Hail. You use Shield of Trust.
2. Shield of Trust blocks Mineral Hail. Girgashiy lands and leans forward, stunned. You use Celestial Spike.
3. Celestial Spike "binds" (or whatever the in-game stuff says) Girgashiy, forcing it onto one knee. You use Judgment Blade.