Prayer, fasting, vigil and all other Christian activities, however good they may be in themselves, do not constitute the aim of our Christian life, although they serve as the indispensable means of reaching this end. The true aim of our Christian life consists in the acquisition of the Holy Spirit of God. As for fasts, and vigils, and prayer, and almsgiving, and every good deed done for Christ’s sake, they are only means of acquiring the Holy Spirit of God. But mark, my son, only the good deed done for Christ’s sake brings us the fruits of the Holy Spirit. All that is not done for Christ’s sake, even though it be good, brings neither reward in the future life nor the grace of God in this. That is why our Lord Jesus Christ said: He who gathers not with Me scatters (Luke 11:23). Not that a good deed can be called anything but gathering, since even though it is not done for Christ’s sake, yet it is good. Scripture says: In every nation he who fears God and works righteousness is acceptable to Him (Acts 10:35)…
Of course, every good deed done for Christ’s sake gives us the grace of the Holy Spirit, but prayer gives us it most of all, for it is always at hand, so to speak, as an instrument for acquiring the grace of the Spirit. For instance, you would like to go to Church, but there is no Church or the Service is over; you would like to give alms to a beggar, but there isn’t one, or you have nothing to give; you would like to preserve your virginity, but you have not the strength to do so because of your temperament, or because of the violence of the wiles of the enemy which on account of your human weakness you cannot withstand; you would like to do some other good deed for Christ’s sake, but either you have not the strength or the opportunity is lacking. This certainly does not apply to prayer. Prayer is always possible for everyone, rich and poor, noble and humble, strong and weak, healthy and sick, righteous and sinful…
St. Seraphim of Sarov’s Conversation With Nicholas Motovilov
http://orthodoxinfo.com/praxis/wonderful.aspx