This poem is written by an adult speaker looking back on how he thought of his father when he was a child and then comparing that to the understanding and wisdom that age has given him now. The line "No one ever thanked him," at the end of the first stanza, confirms the way in which the speaker and other family members completely took his sacrificial action of getting up so early on Sundays for granted. Although he does it to warm the house up for them before they got up, they never thanked him. In addition, the speaker describes how he spoke "indifferently" to his father when he came down, even though his father has polished his shoes for him.
The final lines of the poem show how greatly the poet's view has changed of his father now he is an adult himself:
What did I know, what did I know
of love’s austere and lonely offices?
The sudden change of lexis with the words "austere" and "lonely offices" indicate the change of tone, which is supported by the repetition of "What did I know." These last two lines show that the speaker now feels considerable guilt for the way that he took his father for granted and that now he recognises that what his father did every Sunday morning was a real act of sacrificial love.