It is clear that the term "sacerdotes" from the second sentence refers to presbyters, whereas "antistites" refers to bishops. The ordination to all three higher grades is described as "consecratio". The canon clearly favours clerical continence, describing it as having been established by the Apostles and tradition. The reasons seem to be twofold: firstly, the canon refers to "serving the altars" as the argument for maintaining chastity; it is believed that God will more willingly accept the prayers of chaste people. Secondly, it reminds the clerics that they are "guardians of chastity", meaning probably that they have a role in propagating it as an ideal of Christian life, and therefore must maintain it themselves.
The canon talks about "sacraments" but the reference to the "altars" makes us think that it refers specifically to the Eucharist.