Fr. Nicholas Walsh, S.J., "Supernatural And Conducive To Eternal Salvation"

It is a divine truth that Grace, the Grace of God, is the only power or means by which man’s soul is sanctified and saved. With it we can do all things, and without it nothing; nothing, in itself, supernatural and conducive to eternal salvation. It is also the teaching of the Church that Prayer and the Sacraments are the great channels of Grace instituted by Jesus Christ. He says to all:  “Ask and you shall receive.” After His resurrection, He instituted the Sacrament of Penance, or Confession, as it is commonly called, when “He breathed on the Apostles and said: Receive, all you, the Holy Ghost, whose sins you shall forgive they are forgiven them, and whose sins you shall retain they are retained.” The Apostles, in whom He founded His Church, were a moral body, to last to the end of time, in the exercise of the ordinary powers He gave them, and amongst these was the power of forgiving. Lastly, in the sixth chapter of Saint John, when promising to institute the Blessed Sacrament, 

He said: “Amen, Amen, I say unto you, unless you eat the flesh of the Son of Man, and drink His Blood, you shall not have life in you. He that eats My Flesh and drinks My Blood has everlasting life, and I will raise him upon the Last Day. For My Flesh is meat indeed, and My Blood is drink indeed. He that eats My Flesh and drinks My Blood abides in Me and I in him.” 

Prayer, and the Sacraments of Penance (or Reconciliation) and the Eucharist, are the great ordinary channels of grace between God and the soul of adult man. Of these three, however, Prayer and the Sacrament of Penance are more important, for the following reason. The Eucharist, it is true, has in itself the power of producing grace, but the amount of grace it imparts to the soul depends on the dispositions of the soul when receiving it. A soul very perfectly disposed will receive overflowing grace, whilst to a soul, not in mortal sin, but lukewarm, tepid, in a word, poorly disposed, probably but little grace is given; and of such a Communion the best and worst thing which can be said is that it is not a sacrilege. Now, Prayer and Confession are the great means for preparing and disposing a soul for a worthy and fruitful communion; therefore, in this sense, at least, the former are of more importance than the latter. It is true that a person who receives well the Blessed Sacrament is likely to pray devoutly and to make good Confessions, but still it may be safely said that the Eucharist is not the means towards Prayer and Confession being made well, as these are towards a worthy Communion. 

Link (here) to the Catholic Truth Society to read the full piece by Fr. NicholasWalsh, S.J. entitled Prayer Made Easy