When one is in a difficult situation, a tower of strength can be a helpful resource for support and guidance. There are many different synonyms for the phrase "tower of strength in time of need," including pillar of support, rock, shoulder to lean on, and anchor. These words all suggest a dependable and stable presence that can help someone weather a challenging situation. Other synonyms include champion, defender, protector, and guardian, which imply a sense of protection and advocacy for those in need. Ultimately, the choice of synonym depends on the context of the situation and the specific qualities that one values most in a source of strength and support.