Numbers 32:23

But if ye will not do so
As they promised they would, and Moses insisted on it that they should:

behold, ye have sinned against the Lord
making such a request, and not fulfilling the conditions on which it was granted:

and be sure your sin will find you out;
fly in their faces, accuse them in their consciences, charge and load them with guilt, and bring deserved punishment upon them: sin may be put, as it often is, for the punishment of sin, which sooner or later will find out and come upon the impenitent and unpardoned sinner.