"念には念を入れよ" meaning in 日本語

{
  "categories": [
    {
      "kind": "other",
      "name": "日本語",
      "parents": [],
      "source": "w"
    },
    {
      "kind": "other",
      "name": "日本語 成句",
      "parents": [],
      "source": "w"
    }
  ],
  "forms": [
    {
      "form": "ねんにはねんをいれよ"
    }
  ],
  "lang": "日本語",
  "lang_code": "ja",
  "pos": "phrase",
  "pos_title": "成句",
  "senses": [
    {
      "categories": [
        {
          "kind": "other",
          "name": "日本語 ことわざ",
          "parents": [],
          "source": "w"
        }
      ],
      "glosses": [
        "一度大丈夫だと思っても、本当に大丈夫か何度も確かめるべきだ。"
      ],
      "id": "ja-念には念を入れよ-ja-phrase-4NcLs9bZ",
      "raw_tags": [
        "ことわざ"
      ]
    }
  ],
  "tags": [
    "idiomatic"
  ],
  "word": "念には念を入れよ"
}

{
  "categories": [
    "日本語",
    "日本語 成句"
  ],
  "forms": [
    {
      "form": "ねんにはねんをいれよ"
    }
  ],
  "lang": "日本語",
  "lang_code": "ja",
  "pos": "phrase",
  "pos_title": "成句",
  "senses": [
    {
      "categories": [
        "日本語 ことわざ"
      ],
      "glosses": [
        "一度大丈夫だと思っても、本当に大丈夫か何度も確かめるべきだ。"
      ],
      "raw_tags": [
        "ことわざ"
      ]
    }
  ],
  "tags": [
    "idiomatic"
  ],
  "word": "念には念を入れよ"
}