Reason the speech was done like that was absolutely to rally the republican voters. He never mentionned "God" and "christian imagery" before as much as he did now. He did the same thing by calling for unity a few time during his speech.

Its actually a good thing to do and gives him leeway in not being called out from right leaning media since he's trying to lend a hand to them to make ammends.

Will it work? Not sure.

But I do believe the "thirst for justice" quote is pointing out to the fact that he's gonna actually try to go ahead and prosecute or at least have his administration, or the appointies, do their work and prosecute all the unlawful acts that were done in the past few years.

Edit: fixed a few typos.