OpenGL problem shader program

gistfile1.txt

#version 330 core

layout(location = 0) in vec3 vertexPosition_modelspace;
uniform mat4 MVP;

void main(){
    vec4 v = vec4(vertexPosition_modelspace,1); // Transform an homogeneous 4D vector

    gl_Position = MVP * v;
	//mat4 M = mat4(
	//	vec4(1.0, 0.0, 0.0, 0.0),
	//	vec4(0.0, 1.0, 0.0, 0.0),
	//	vec4(0.0, 0.0, 1.0, 0.0),
	//	vec4(0.0, 0.0, 0.0, 1.0)
	//);
	//gl_Position = M * v;
}