Mark 11:2

And saith unto them, Go your way into the village that is over against you: and straightway as ye enter it, ye shall find a colt tied, whereon no man ever yet sat; loose him and bring him.

As to which village was meant, there is no certain way to determine it; but Matthew's mention of their coming to Bethphage with no mention of Bethany suggests that the latter was the "village over against" them. Mark and Luke writing at a later date than Matthew threw in the name of the village where they got the colt. This writer is aware that this contradicts the notions regarding Mark's being the first gospel; but this is only one of a hundred examples in the text itself suggesting the priority of Matthew, a position which this writer accepts as far more likely to be true. The historical fact of Matthew's being the first book in the New Testament is of immense weight.

A colt tied ... The mother would not depart from the colt if the latter was tied, hence it was unnecessary to tie both animals. Tying the mother, on the other hand, would not restrain the colt from wandering off. Both were tied.