Light escaping from stars despite their mass? 
"Light is deflected by powerful gravity, not because of its mass (light has no mass) but because gravity has curved the space that light travels through."

If the Mass of the Sun is so great, how is it that the light from the Sun reaches Earth and other planets? Wouldn't it's gravity keep the light from 'reaching out'?
Is there any equation relating this?
 A: The mass of the sun isn't anywhere near great enough to keep its radiation from escaping.  Not even close.
Look up something called a black hole.  That's a large enough mass within a small enough radius so that light can't escape.  Note that the mass required for something the size of the sun is much much greater than the sun, or the size for something the mass of the sun is much much smaller than the sun.
The concept is correct, but ordinary main sequence stars don't even come close to it.
A: 
If the Mass of the Sun is so great, how is it that the light from the Sun reaches Earth and other planets? Wouldn't it's gravity keep the light from 'reaching out'?

The quote in the question appears to be from a biography on Einstein and references the very tiny bending of the light from another star by the Sun's gravitation. This is very small. The Sun is far too large across to prevent light from escaping. Light can easily escape from the Sun because escape velocity at the surface of the Sun is 617.7 km/s, far less than the speed of light (~300000 km/s).

Is there any equation relating this?

Yes. For a non-rotating object, the Schwarzschild radius determines whether an object is so small and so massive that not even light can escape. The Schwarzschild radius is $\frac{2GM}{c^2}$, where $G$ is the Newtonian gravitational constant, $M$ is the mass of the object, and $c$ is the speed of light. The Sun's Schwarzschild radius is about 2 km. Light would not escape an object with the mass of Sun but shrunk down to only 4 km across. The Sun is considerably larger than 4 km in diameter. 
