Is the wife's elder sister permanently forbidden to her sister's husband if she breastfed the wife in her infancy?

If your wife's elder sister breastfed your wife five full feedings while she was within the first two years of life, then she is considered her mother through breastfeeding. Accordingly, your wife becomes permanently forbidden to you upon marriage, due to the Almighty's saying: "and your wives' mothers," and due to the Prophet's (peace be upon him) saying: "What is forbidden by lineage is forbidden by breastfeeding."