A sacrament is an holy ordinance instituted by Christ, wherein, by sensible signs, Christ, and the benefits of the new covenant, are represented, sealed, and applied to believers.1
7 And I will establish my covenant between me and thee and thy seed after thee in their generations for an everlasting covenant, to be a God unto thee, and to thy seed after thee.
10 This is my covenant, which ye shall keep, between me and you and thy seed after thee; Every man child among you shall be circumcised.
1 Corinthians 11:23, 26
23 For I have received of the Lord that which also I delivered unto you, That the Lord Jesus the same night in which he was betrayed took bread:
26 For as often as ye eat this bread, and drink this cup, ye do show the Lord's death till he come.