Luke 14:5

And answered them, saying, Which of you shall have an ass or an ox fallen into a pit, and will not straightway pull him out on the sabbath day?

Cross-references

Luke 13:15 uses the same analogy of loosing an ox or ass on the Sabbath to justify healing.

Matthew 12:11 records the identical saying about rescuing a sheep from a pit on the Sabbath, reinforcing Jesus' argument.

Matthew 12:12 explicitly states the principle: if you save an animal, how much more a person, making the Sabbath healing lawful.