(a) The Church can call to mind those things that are already prescribed by the Divine Law, Natural or Positive; and, although she cannot dispense in these laws (see 313-814 and exception as to hypothetical positive law in 357), she can interpret them authoritatively, and can decide when obligations of the Divine Law, that depend upon an act of the human will, cease (see 315-316). (b) The Church can determine those things that were left undetermined in the Divine Law. Examples: The manner in which the Lord’s Day is to be sanctified, the times and frequency with which the Divine law of Communion is to be fulfilled, the way in which the obligation of fasting is to be complied with, etc. (c) The Church can make laws in matters that were left free by our Lord whenever this will promote the better observance of His law (e.g., many church laws for the clergy and religious, for the conduct of worship, for administration, etc.). 426. The acts that may be commanded by the Church are of various kinds. (a) The Church may command acts that are purely external (e.g., fasting) and acts that are partly external and partly internal, that is, those external acts to which, from the nature of things or from law, a special moral act of the intellect or will must be joined (e.g., a true oath, a worthy confession or Communion). (b) The Church may command acts that are purely internal, that is, acts of the intellect or will that are not necessarily connected with any external act (such as meditation, the intention in applying Mass, ctc.), whenever she is explaining, applying, or determining the Divine Law, or acting in virtue of the power of Christ. Examples: The Pope may define a dogma to be accepted internally. A confessor may impose as penance a pious meditation. The Church prescribes the days when pastors must intend to offer Mass for their people. A religious superior may command a spiritual retreat. (c) It is more probable that, apart from instances such as those just given, the Church cannot legislate regarding acts that are purely internal. For unlike the divine Legislator, who sees the internal acts of the soul and who can pass judgment on them, the Church cannot read the heart or judge the conscience. Hence, it would appear useless for the Church to give commandments about acts that elude her knowledge, all the more so since the Divine Law has given commands and prohibitions regarding internal acts and no one can escape the judgment of God. 427. Those Bound by General Laws.--The general laws of the Church oblige all and only such persons as are at once subjects of the Church and capable of receiving a law (Canon 12).