However, the seal is still a mark; it is not a baggie. You may wish to look up signet ring and the wax seal.
MarkBsnr, The seal in verse 13 is identified as downpayment from God in verse 14, to us, by means of the Spirit, that guarantees there is more to come. It is no idle mark. We are “sealed to the day of salvation” - thankfully!
Not sealed because of anything we have done, but because HE has paid the penalty for each and every sin for us. It is based entirely on His righteousness and not our own. I am betting His blood is sufficient payment, His righteousness will not fail. If His sinless life sacrificed through shed blood, death and His resurrection are not sufficient, there is no hope for anyone.
“Thank God for His indescribable Gift!” - Apostle Paul