Matthew 21:3

“And if any one says anything to you, you shall say, ‘The Lord has need of them', and immediately he will send them.”

It may well be that Jesus had already made an arrangement that He would collect the asses when He needed them and that whoever collected it was to give a kind of password, ‘the Lord has need of them'. Or it may be that He was making use of the custom of ‘angaria' under which a major religious figure was entitled to procure for himself the use of a means of transport for a period of time by a simple act of appropriation. ‘The Lord has need of them' would then be seen as indicating this.

We are in fact probably intended to see in the use of the title ‘the Lord' a deliberate indication that this was an unusual situation by which Jesus' supreme authority was being revealed. ‘The Lord' may refer to God, in Whose Name Jesus was acting, or it may have been the title by which the owners acknowledged Jesus. The whole arrangement thus indicates that Jesus has a special significance in what He is about to do. It may well therefore be that the ass's colt was in fact being offered for His free use as a major religious figure in accordance with the custom of angaria without previous arrangement.