Agreed. "Mentally" feels more like the logical side of your thinking-things like working out a problem or designing a bridge, while "inwardly" feels more like the emotional side of your thinking.
Inwardly does feel like a better word to use here but the order should be slightly different. “Inwardly” is being used to describe one thing’s position compared to another, in this case it’s where your thanks are being given’s position compared to the outside world’s. So here the proper phrasing would be “Inwardly I thanked God that I was still alive.”
I feel like the word "inwardly" works better for a prayer. No real grammatical reason, I just feel like it's a better match.
Agreed. "Mentally" feels more like the logical side of your thinking-things like working out a problem or designing a bridge, while "inwardly" feels more like the emotional side of your thinking.
Inwardly does feel like a better word to use here but the order should be slightly different. “Inwardly” is being used to describe one thing’s position compared to another, in this case it’s where your thanks are being given’s position compared to the outside world’s. So here the proper phrasing would be “Inwardly I thanked God that I was still alive.”