One of the 3 songs ascribed to Moses, it was sung at the borders of the promised land and is a hymn of hope that God has shown his care and love for Israel before and whilst Israel may sometimes go off the path God will not forget them.
As with the song of the sea, this piece of poetry is distinguished from the rest of the text with its split lines with the central space emphasising the two parts to each verse called parallelism, the second part reinforcing the message of the the first.
eg Give ear... let the earth hear
Remember the days of old... consider the years of ages past
You neglected... you forgot