A mikvah is a ceremonial baptism by cleansing in a fresh water source that has an outflow (not stagnant). The couple would individually cleanse in a mikvah before two witnesses prior to the public ceremony.

Then Jesus came from Galilee to John at the Jordan to be baptized by him. And John tried to prevent Him, saying, ‘I need to be baptized by You, and are You coming to me?’ But Jesus answered and said to him, ‘Permit it to be so now, for thus it is fitting for us to fulfill all righteousness.’ Then he allowed Him. Matt 3:13-15

Jesus answered, Most assuredly, I say to you, unless one is born of water and the Spirit, he cannot enter the Kingdom of God. John 3:5

But I have a baptism to be baptized with, and how distressed I am till it is accomplished! Luke 12:50

A mikvah is a ceremonial baptism by cleansing in a fresh water source that has an outflow (not stagnant). The couple would individually cleanse in a mikvah before two witnesses prior to the public ceremony.

Then Jesus came from Galilee to John at the Jordan to be baptized by him. And John tried to prevent Him, saying, ‘I need to be baptized by You, and are You coming to me?’ But Jesus answered and said to him, ‘Permit it to be so now, for thus it is fitting for us to fulfill all righteousness.’ Then he allowed Him. Matt 3:13-15

Jesus answered, Most assuredly, I say to you, unless one is born of water and the Spirit, he cannot enter the Kingdom of God. John 3:5

 
But I have a baptism to be baptized with, and how distressed I am till it is accomplished! Luke 12:50

A Ketubah was an official marriage contract, a covenant, which was fully binding by law. Itemized within were the promises and provisions that the groom made to his bride. God’s first Ketubah (covenant) with His Bride Israel was called the Covenant of the Law written on tablets of stone. In the New Covenant Ketubah, was promised as God writing His Word on our hearts,

Behold, the days are coming, says the Lord, when I will make a new covenant…though I was a husband to them… But this is the covenant that I will make with the house of Israel…I will put My law in their minds, and write it on their hearts; and I will be their God, and they shall be My people. Jerm 31:31-33

…who (Gentiles) show the work of the law written in their hearts, their conscience also bearing witness…in the day when God will judge the secrets of men by Jesus Christ, according to my gospel. Rom 2:15-16

Both the bride and groom commit to specific responsibilities during their time of separation to prepare for one another.