«صَنْعَةْ بِلَا اسْتَادْ يِدْرِكْهَا الْفَسَادْ»

The saying holds that a craft learned without a master (استاد, a colloquial form of أستاذ, meaning a master craftsman or trainer, not an academic professor) will end up flawed. Proper technique comes through apprenticeship and correction from someone experienced. Self-taught work, however confident, tends to carry hidden faults that eventually spoil it.

More broadly, it can apply to any undertaking lacking competent guidance, whose quality slowly decays without someone to set standards and catch mistakes. A variant reading uses يركبها ('mounts it') for يدركها ('overtakes it') with the same sense. The rhyme of استاد with فساد gives the saying its punch, which plain English loses.

Use this when someone tries to pick up a skilled trade or practice on their own, skipping instruction, and the results show it. It also fits as a warning before taking up a craft, urging the person to find an experienced teacher to learn under first.