To escape the gravitational field of an object such as a planet or star, you need to be travelling at a certain minimum speed, or eacape velocity. IIRC the escape velocity at the surface of the earth is about 11 km/s. The escape velocity of a black hole is greater than the speed of light. Since nothing can move faster than light nothing can escape from a black hole.

According to the Theory of Relativity, light does have mass and is affected by gravitational fields. Light cannot escape from a black hole. It would actually be more accurate to say no electromagnetic radiation can escape. Hawking radiation is emitted from the space around a black hole.