In verse 5 Abraham discloses that he thinks they have only called in order to take refreshment. Why did the Lord and the two angels come as three men? Perhaps so that they should not immediately be recognised – a little test for Abraham.
This was no doubt characteristic of the way Abraham interacted with strangers, although Calvin says, ‘if he had slaughtered calves for all kinds of travellers, his house would soon have been emptied by his profuse expenditure’ and argues that he saw some unusually ‘excellent endowments’ in these three persons. It is a great test of character to see how we conduct ourselves with strangers. We know little about them at first. There is no question of us paying back a debt, so how will we treat them? Will we react humbly and honour them above ourselves? This was probably one of the events in mind when the writer of Hebrews speaks of entertaining angels unawares (Hebrews 13:2). If so it confirms that Abraham did not realise who they were at first. God’s people show hospitality to stranger in the confidence that thy will not be the loser, for what we give to strangers, we give to the Lord.