[..that he] would not touch the painting, nor finish it unless the claimant pays him the balance due or guarantees it by giving a security.

Rembrandt is rejecting the demand of the Portuguese Jewish merchant Diego d'Andrade, who rejected in 1654 the portray of his daughter which Rembrandt was painting, as "showing no resemblance at all to the head of the young daughter". D'Andrade demanded that Rembrandt immediately take up his brushes and finish the work to his satisfaction