The "Mystery of Anointing", as the Greek Churches call it, is a Sacrament that, like Holy Communion, has waxed and waned in the frequency of the faithful availing themselves to its graces. Anointing had a place quite apart from Holy Communion until the Middle Ages, when in the Latin Church it was administered with Confession and the Eucharist to comprise the "Last Rites." Anointing figures prominently in the Old Testament, where the prophets of God imparted Divine authority unto those chosen as kings and priests; even in the Middle Ages, many considered the anointing of kings at their coronation to be like a Sacrament. Similarly, the use of anointing consecrated those ordained to Divine service under the new covenant: the priesthood of all believers (Confirmation/Chrismation), the lower order of priesthood (priestly ordination), and the higher degree of priesthood (episcopal consecration). Uniquely, in the New Testament the Church uses anointing for the expressed purposes of healing, following Christ's co-mingling of earthly substances with grace as He did in scrubbing a blind man's eyes with mud and paste.
There is an allusion to the healing Sacrament of Unction in the writings of Saint, and one time anti-Pope, Hippolytus:
"If anyone offers oil, let him [the bishop] give thanks in the same way as for the offering of bread and wine [not using the same words but expressing the same idea] and say, ‘Lord, just as by sanctifying this oil, with which you anointed kings, priests and prophets, you give holiness to those who are anointed with it and receive it, so let it bring comfort to those who taste of it and health to those who use it’." Apostolic Tradition VSs. Ambrose and Augustine are recorded as having visited their flock to administer the Sacrament of Unction personally and to pray for the physical healing of the infirm. The old Roman ritual for Unction explicitly invoked the forgiveness of sins ("may the Lord pardon you of whatever sin you have committed by [sight, smell, etc....]") and the restoration of the anointed one's health ("by the grace of the Holy Spirit the ailments of this sick person and heal his (her) wounds, forgive his (her) sins, drive from him (her) all pains of mind and body and in Thy mercy restore him (her) to full health within and without, that being cured by the help of Thy mercy he (she) may return to his (her) former duties"). At this same time when Unction was delivered regularly to the faithful, Communion was approach irregularly in much of the Church. Communion of all eligible recipients seems to have been normal in Rome; the deacon ritually expelled the un-baptized, those in penance, and heretics before the Gospel. In the Greek Church, if St. Ambrose is to be trusted in de Sacramentis (V.4.25), the faithful only communicated once a year; towards the end of the first millennium, general Communion died in Rome and frequent Unction with it. By contrast, the Greek Church expanded the use of Unction to Wednesday of Holy Week, so that those unable to attain Confession with a monk (Greeks were never fond of confessing to married clergy) could have their sins remitted and communicate on Pascha. Sacrosanctum Concilium (73-75) asked that the Sacrament be received more frequently and, like all other rites, that the ritual be revised for no obviously useful reason.
Despite their lack of obvious congruity in reception (like Baptism and Communion, or Confession and Communion), the Sacraments of Anointing and Communion have shared a remarkable pulse in Latin Christendom. Nowadays both Sacraments are abused by overuse. I can recall several "healing Masses" as a child and college student when the priest gave the Sacrament of Unction to whoever wanted it, regardless of the state of their souls or health. I will not reiterate the obvious abuse of Communion and the infrequency of Confession in detail. As is usual, mainstream traditionalists are the odd ones out here: at the local FSSP church 95% of people communicate at a given Mass (no doubt after going to the generously available Confessors), but Unction non extremis is frowned upon. Papa Sarto encouraged "frequent" Communion in an age when, for fear of unworthy reception, Catholics generally followed the decree of Lateran IV which required the faithful to approach at least during Paschaltide and one other time every year (they had communicated even less often before that).
Sacraments require preparation, and being "in the state of grace" may not always be enough to make a worthy reception of the Eucharist, although it is enough to avoid a blasphemous one. Just as a man goes through months of preparation for marriage, years of study for ordination, and parses his heart prior to Confession, so he should make wise and generous use of Communion and Anointing after sufficient readiness through appropriate means of penance, fasting, prayer, and other means the Church has sanctioned through the centuries. Perhaps then both Sacraments will then be "approach[ed] with the fear the God, with faith and with love".