The version with the words, "arm-in-arm down the road like sister and brother" began to be heard only recently. The more commonly sung version (and older I think) goes thus:

As I went out walking one morning in May,
I met a fair couple a-making their way;
And one was a lady so sweet and so fair
And the other was a soldier, a brave volunteer.

Good morning, good morning, good morning to thee,
O where are you going, my pretty lady?
I'm going a-walking on the banks of the sea
To see the waters a-gliding, hear the nightengales sing.

They had not been standing but an hour or two
When out from his knapsack a fiddle he drew,
And the tune that he played made the valleys all ring-
O harken, said the lady, how the nightengales sing!

Pretty lady, pretty lady, it's time to give o'er.
O no, pretty soldier, play just one tune more
For I'd rather hear your fiddle- just the touch of one string,
Than hear the waters a-gliding, hear the nightengale sing.

Pretty soldier, pretty soldier, won't you marry me?
O no, pretty lady, that never can be
For I have a wife in London and children twice three,
Two wives and six children's too many for me!

I'll go back to London and stay for one year
And so often I'll think of you my little dear,
And if ever I return it will be in the spring,
To see the waters a-gliding, hear the nightengale sing.

These are probably the lyrics, or near them, sung by Burl Ives. Also, in the course of my long life, I found a North Carolina version, probably a parody, has humor of the period and is quite charming. I'll give lyrics if they're wanted.    Jean