Praise be to Allaah.
Striking is a breach of the contract between the worker and his employer, and Allaah calls on us in His Book to honour and uphold the contracts that one person may take upon himself towards another person. So the worker has to do all the work that he agreed to do in a manner that pleases Allaah and in accordance with the aayah (interpretation of the meaning);
“O you who believe! Fulfil (your) obligations…”[al-Maa’idah 5:1]