Light will never be at rest, it always travels at the speed of light, so the question has no meaning. You can, however, calculate the energy of light of a particular frequency, then calculate the equivalent mass, then calculate what the force of gravity would be on that. Wouldn't really tell you anything useful though, you need the equations of general relativity and a far deeper understanding of them than you or I have to get it right.
The formulas were based on that and I didn't even attempt to 'run it'. lol, still, in theory, mass doesn't always have to be in motion to keep it's mass (and the weight that goes with having mass)
Here is the background that made me ask that question.
In one instance travel in space was the topic and the two theories was a sail. If it could collect light and that would provide the needed thrust. My question concerned the other end, once you start to approach a distant star that light would be acting to halt your progress in that direction so it would seem a true sail would only get you stranded a long distance from any star so it's usefulness is zero. Point two was along that same example. When you consider that mass attracts mass (even in space where zero gravity is possible) then if two independent heavenly bodies are attracted to each other then total mass should dictate which object is drawn off course, the smaller of the two is the ones to alter course. The mass of the sail and the ship that is holding it all together would be greater than the force any (visible) light could overcome.
Question two was similar but instead of a sail it was a 'flashlight' and the question was could it propel itself through space. Again that mass vs available thrust comes into play. One other aspect could also affect the way it works. Energy is said to be impossible to create or destroy. In a flashlight holds the energy and it is some of the total mass of the flashlight. A battery is stored energy so it comes 'pre-wound' and flipping the switch allows some of that stored energy to be converted into light. Wouldn't light qualify as the transfer medium (space with a predetermined distance) and if it was related to mass the reflections could not be possible.
That brings up the final part of the journey. We see stars in the heavens because they shed light, to do that they have to meet certain requirements along the mass,density parameters. When a star gets very close to the event horizon of a black hole (center od all galaxies that are imploding) it is said to accelerated past the speed of light and gravity is so great not even light can escape. With that shift in gravity why does a star still shed light when the parameters that allowed it go give light are most likely exceeded and the body that captured the mass that used to be a sun has not yet reached it critical point where it starts to 'shed mass' (via the 'polar regions' of a galaxy)
I promise that brings it up to date an no follow-ups. With the OP appearing to be hard to pin down has it been established if he is talking about his own faith, etc or is it about the faith in others? From the few post I have read he seems to be suffering from something similar to the Jerusalem Syndrome (a term that was actually used to describe some Christian going bonkers once they enter Jerusalem (a place where Judaism rules). ^The vid I saw had them (one at a time never more than that) could have been on PCP, not that he was dangerous just really messed up in the way he moved from point "A" to point "B". The 'cure' for that person (staged for the Christian tourists BTW) would be to grab him by the collar, spin him around and deliver a stinging right-hand (or left, whichever is strongest) , as soon as his eyes 'clear' hold him close an deliver a knee to the groin (with your weakest leg) if he was at all slouched over he will now be standing straight and tall. The slap is actually a real treatment for some types of shock, the knee in this case is because he's giving Jesus a bad name by his antics. I have no idea how to deliver a virtual slap.
Later
Only to those that have comprehension issues.
Yep, denoting a title. As apposed to the orifice from which the bulk of your opinions are gleaned from.
So a typing finger is an orifice and I have the comprehension issue? You must be getting help, one person cannot be that stupid all by themselves. lol Just a line don't take it to heart.