'Posterity' in the Bible

Speak unto the children of Israel, saying, If any man of you or of your posterity shall be unclean by reason of a dead body, or be in a journey afar off, yet he shall keep the passover unto the LORD.

All the offerings of the holy things, which the Israelites offer to the Lord I have given to you and to your sons and your daughters with you as a continual allotment. It is an everlasting covenant of salt [that cannot be dissolved or violated] before the Lord to you and to your descendants with you.”