"And it came to pass that when he said these words, he commanded his Disciples that they should take of the wine of the cup and drink of it, and that they should also give unto the multitude that they might drink of it."
In this description we do not have mention of the blessing pronounced upon the wine. Moroni will later clarify that it was blessed and provide us the words of His blessing: "The manner of administering the wine—Behold, they took the cup, and said: O God, the Eternal Father, we ask thee, in the name of thy Son, Jesus Christ, to bless and sanctify this wine to the souls of all those who drink of it, that they may do it in remembrance of the blood of thy Son, which was shed for them; that they may witness unto thee, O God, the Eternal Father, that they do always remember him, that they may have his Spirit to be with them. Amen." (Moroni 5: 1-2.)
Once again it is a "command" to partake. The Lord, knowing how critical this act is for salvation and a testimony before the Father, makes it a command that the disciples drink of it.
Wine was generally either purple or red. Our blood is purple when deprived of oxygen in our veins, and red when filled with oxygen in our arteries. These two colors of blood inside our bodies are akin to the predominate colors of wine.
Once again it is the disciples who partake first. Then, after having partaken, they pass it to the multitude. This illustrates the practice of receiving it before being able to pass it to others. It is not possible to pass along what has not first been received. This is true of all the Lord's ordinances. It is one of the reasons Alma rebaptized himself the instant he first began to baptize others. (Mosiah 18: 14.) Those who bless are to be sanctified by partaking, then they pass the sacrament as sanctified ministers. Those who are passing are not more important, but rather they are first purified. Then those to whom they minister may receive the ordinance from those who are already clean.