All the firstborn males that are born of your herd and of your flock you shall sanctify to the LORD your God: you shall do no work with the firstborn of your herd, nor shear the firstborn of your flock.

If a man have two wives, the one beloved, and the other hated, and they have borne him children, both the beloved and the hated; and if the firstborn son be hers who was hated;

The children of the third generation who are born to them shall enter into the assembly of the LORD.