Wherein do the sacraments of baptism and the Lord's supper agree?

The sacraments of baptism and the Lord’s supper agree, in that the author of both is God;[1] the spiritual part of both is Christ and his benefits;[2] both are seals of the same covenant,[3] are to be dispensed by ministers of the gospel, and by none other;[4] and to be continued in the church of Christ until his second coming.[5] 

1. Matt. 28:19 

   Go therefore and make disciples of all nations, baptizing them in [1] the name of the Father and of the Son and of the Holy Spirit…

   I Cor. 11:23

   For I received from the Lord what I also delivered to you, that the Lord Jesus on the night when he was betrayed took bread…

2. Rom. 6:3-4

   Do you not know that all of us who have been baptized into Christ Jesus were baptized into his death? We were buried therefore with him by baptism into death, in order that, just as Christ was raised from the dead by the glory of the Father, we too might walk in newness of life.

   I Cor. 10:16 

   The cup of blessing that we bless, is it not a participation in the blood of Christ? The bread that we break, is it not a participation in the body of Christ?

3. Rom. 4:11

   He received the sign of circumcision as a seal of the righteousness that he had by faith while he was still uncircumcised. The purpose was to make him the father of all who believe without being circumcised, so that righteousness would be counted to them as well….

   Col. 2:12

   …having been buried with him in baptism, in which you were also raised with him through faith in the powerful working of God, who raised him from the dead.

   Matt. 26:27-28

   And he took a cup, and when he had given thanks he gave it to them, saying, “Drink of it, all of you, for this is my blood of the covenant, which is poured out for many for the forgiveness of sins.

4. John 1:33

   I myself did not know him, but he who sent me to baptize with water said to me, ‘He on whom you see the Spirit descend and remain, this is he who baptizes with the Holy Spirit.’

   Matt. 28:19

   Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit….

   I Cor. 4:1

   This is how one should regard us, as servants of Christ and stewards of the mysteries of God.

   1 Cor. 11:23

   For I received from the Lord what I also delivered to you, that the Lord Jesus on the night when he was betrayed took bread…

   Heb. 5:4

   And no one takes this honor for himself, but only when called by God, just as Aaron was

5. Matt. 28:19-20

   Go therefore and make disciples of all nations, baptizing them in the name of the Father and of the Son and of the Holy Spirit, teaching them to observe all that I have commanded you. And behold, I am with you always, to the end of the age.

   I Cor. 11:26

   For as often as you eat this bread and drink the cup, you proclaim the Lord’s death until he comes.

 Question 176, Westminster Larger Catechism