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.
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.
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.
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).