The point of water Baptism is answered by Matthew in chapter 28: 18And Jesus came and spake unto them, saying, All power is given unto me in heaven and in earth.
19Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost:
20Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you always, even unto the end of the world. Amen.
Verse 19 is clear baptism must occur.
As far the Lord's Table Christ made it clear what it was about and who should partake.
Luke 22: 19And he took bread, and gave thanks, and brake it, and gave unto them, saying, This is my body which is given for you: this do in remembrance of me.
20Likewise also the cup after supper, saying, This cup is the new testament in my blood, which is shed for you.
This do in remembrance of Me Christ said. The Lord's Table is a time of remembrance of what He did for us. When observed it should be done as a very special occasion. All sin should be confessed by anyone partaking of it. Who did Christ serve that night, His followers. Who should be allowed to partake those that are Christ. He made it clear in Matthew 28:20 those who have followed His commandments of which one was to be baptised. The other to Love one another as He loved us. It is a time of remembrance of the things He did for us in giving His body and shedding His blood to pay the penalty for our sins. No where in scripture will you find the command that the participants must be a member of a specific brand of church to partake. Paul made it clear that those who do partake must ensure that they are worthy, that means it isn't my place to determine that. But as a solemen sacred service which is a very rare thing these days those not worthy would realize their need for confession and fellowship with God before they partake of it. I rarely partake of the Lord's Table today, not because I am unworthy but because of the way it is conducted. It appears to me to be just soemthing we do because that what we are supposed to do, I even heard a guy comment after our Pastor concluded serving the Table following the morning service that he wanted two of the wafers and only received one, what are we coming too when we don't revernce the time. I have a hard time with a serving the Lord's Table after the regular morning service because their is no memorial no sacred time to ensure you are worthy, just conduct the normal service and then business as usaul serving the Table. I want this time to be a special and sacred time a time for the Family members the members of God family to reflect on what Christ did for us and then check to see that we are worthy to participate, that is the important thing, as often as ye do this do it in REMEBRANCE OF ME!