CPC Law: Section 149 – Liability of Partners

Ab bas, let's say, X, Y, and Z are partners in a firm. They're all in on a business deal, but somehow things fall apart, and they end up owing huge sums to a bank. The bank sues the firm, but the partners claim they were all just "sleeping giants" during the deal. The firm's insolvent, and the bank's asking for a personal guarantee from the partners. Who's responsible here? Is it the firm, or the partners individually? Or, maybe, it's a bit of both? What's the CPC section that'll come to the rescue here?