Sayyidul Istighfar

When. Morning and evening, and it is one of the fixed items in both sets. The name means "the master of seeking forgiveness" — a title given for its structure, not its length.

The words. Almost none of it is a request. The text printed here contains no asking at all: it establishes a relationship, then states a position. Anta Rabbi — You are my Lord — then the declaration of oneness, then khalaqtani wa ana 'abduk, You created me and I am Your servant. Creation is given as the reason for servanthood, in that order, cause before consequence.

Then the clause that most people notice: wa ana 'ala 'ahdika wa wa'dika mastata't — "as best I can". Mastata't is a limiting clause, and it is placed in the middle of an affirmation rather than at the end as an excuse. The speaker claims to be keeping the covenant and admits the claim is partial, in one breath, before any forgiveness is mentioned.

The rest of it. The full text continues past what is quoted here, seeking refuge from what one has done, acknowledging the blessing and the sin together, and asking for forgiveness with the reason given: none forgives sins but You.

Why it is called the master. It contains what other supplications for forgiveness contain separately — affirmation of lordship, acknowledgement of creation, admission of shortfall, confession, and only then the request. The asking is the last thing that happens.

On memorising it. It is longer than most daily formulas and takes real effort to learn. Nobody arrives at it first; it is usually the one a person adds after the short ones are settled.