Even if you have only bread or water, with these you can still meet the dues of hospitality. Even if you do not have these, but simply make the stranger welcome and offer him a word of encouragement, you will not be failing in hospitality. Think of the widow mentioned in the Gospel by our Lord: with two mites she surpassed the generous gifts of the wealthy.
Even a pious person is not immune to spiritual sickness if he does not have a wise guide -- either a living person or a spiritual writer. This sickness is called prelest, or spiritual delusion, imagining oneself to be near to God and to the realm of the divine and supernatural. Even zealous ascetics in monasteries are sometimes subject to this delusion, but of course, laymen who are zealous in external struggles (podvigi) undergo it much more frequently. Surpassing their acquaintances in struggles of prayer and fasting, they imagine that they are seers of divine visions, or at least of dreams inspired by grace. In every event of their lives, they see special intentional directions from God or their guardian angel. And then they start imagining that they are God's elect, and often try to foretell the future. The Holy Fathers armed themselves against nothing so fiercely as against this sickness -- prelest.
A great effort and much toil are needed in prayer before we can reach a state in which our mind is no longer troubled, and so attain the inward heaven of the heart where Christ dwells. As St. Paul says, 'Do you not realize that Christ dwells within you, unless you are worthless?' (cf. 2 Cor. 13:5).
Fire makes iron impossible to touch, and likewise frequent prayer renders the intellect more forceful in its warfare with the enemy. That is why the demons strive with all their strength to make us slothful in attentiveness to prayer, for they know that prayer is the intellect's invincible weapon against them.
If you are a friend of Christ you should have as friends persons who are of benefit to you and contribute to your way of life. Let your friends be men of peace, spiritual brethren, holy fathers. It is of such that our Lord was speaking when He said: 'My mother and brethren are those who do the will of My Father who is in heaven.' (cf. Matt. 12:49-50).
Unless the inner man meditates upon the law of God and is nourished thereby, unless he is strengthened by reading and by prayer, he is conquered by the outer man, and he serves his master.
The adversary of our life, the devil, employs many devices to make our sins seem small to us. Often he cloaks them with forgetfulness, so that, after suffering a little on their account, we no longer trouble to lament over them. But, my brethren, let us not forget our offences, even if we wrongly think that they have been forgiven through repentance; let us always remember our sinful acts and never cease to mourn over them, so that we may acquire humility as our constant companion, and thus escape the snares of self-esteem and pride.
Peter was first given the keys, but then he was allowed to fall into the sin of denying Christ; and so his pride was humbled by his fall. Do not be surprised, then, if after receiving the keys of spiritual knowledge you fall into various evil thoughts. Glorify our Lord, for He alone is wise: through setbacks of this kind He restrains the presumption that we tend to feel because of our advance in the knowledge of God. Trials and temptations are the reins whereby God in His providence restrains our human arrogance.
Be not forgetful to entertain strangers: for thereby some have entertained angels unawares. (Heb. 13:2) Accepting the task of hospitality, the patriarch [Abraham] used to sit at the entrance to his tent (cf. Gen. 18:1), inviting all who passed by, and his table was laden for all comers including the impious and barbarians, without distinction. Hence he was found worthy of that wonderful banquet when he received angels and the Master of all as guests. We too, then, should actively and eagerly cultivate hospitality, so that we may receive not only angels, but also God Himself. 'For inasmuch,' says the Lord, 'as you have done it to one of the least of these My brethren, you have done it unto Me' (Matt. 25:40). It is good to be generous to all, especially to those who cannot repay you.
Suppose you have ordered yourself not to eat fish; you will find that the enemy continually makes you long to eat it. You are filled with an uncontrollable desire for the thing that is forbidden. In this way you can see how Adam's fall typifies what happens to all of us. Because he was told not to eat from a particular tree, he felt irresistibly attracted to the one thing that was forbidden him.
'Then the devil left Him, and angels came and ministered to Him' (Matthew 4:11). It does not say that the angels were with our Lord during the actual time when He was being tempted. In the same way, when we are being tempted, God's angels for a time withdraw a little. Then, after the departure of those tempting us, they come and minister to us with divine intellections, giving us support, illumination, compunction, encouragement, patient endurance, joyfulness, and everything that saves and strengthens and renews our exhausted soul. As Nathaniel was told, 'You will see the angels ascending and descending upon the Son of man' (John 1:51); in other words, the ministry and assistance of the angels will be given generously to mankind.
Do all in your power not to fall, for the strong athlete should not fall. But if you do fall, get up again at once and continue the contest. Even if you fall a thousand times because of the withdrawal of God's grace, rise up again each time, and keep on doing this until the day of your death. For it is written, 'If a righteous man falls down seven times' - that is, repeatedly throughout his life - 'seven times shall he rise again' [Prov. 24:16].