His life is come to an end because he feels that he is 'lost' without his son. He uses the word 'wandering' for this condition. Now he has no special purpose in his life and he feels like nothing important left since he lost his son whom he loves so much. However, his memory of his son is still there and it might be his reason why he is still alive. This memory is his 'strong base' to continues his life. This 'strong base' is represented by the word 'foundations' (line 3). The first line 'And we, what are we' is meant to emphasize his desperate feelings.
In the second stanza, we can notice metaphors, symbols and apostrophe. We can see metaphors as he compares his son to an olive tree and a palm tree. As an olive tree, he wants his son to 'blossoms and promises fruit'. That is, to grow healthy ('blossoms') and to have a child ('promises fruit'). The father also wants him to 'bears within it a riddle of ripe and age'. This means to handle any difficulties that will come in his life as he grows old. 'Ripe and age' compares to grow old because 'ripe' means fully developed (which is suitable to 'age'). Then, as a palm tree, he wants his son to be 'Rooted by the banks of flowing rivers' which