Actually there's two bits in numbers that touch on it. The first time in Exodus 21 was how much restitution is owed if a woman is struck hard enough to miscarry. (This passage is often purposely mangled in translation to being something about "dropping an apple" or other nonsense, for obvious reasons) The second, in Numbers 5, describes what was likely an abortion procedure administered by a rabbi.

There are also multiple points at which it is clearly stated that ensoulment happens after the body is formed, all phrased different ways. Gen 2:7 says Adam was not given a soul until God gave him his first breath. Job 33:4 says that "the spirit of god has made me, and the Breath of the almighty has given me life", once again stating that the body is formed before the breath of life is given. There are many other points, but you get my meaning. The most literal way of reading this is that ensoulment happens at the first breath, but I think a more reasonable interpretation is that "breath of life" is metaphorical and therefore life should be considered to begin at the quickening, when the baby's body and brain are developed and they start moving around.

I haven't found any part of the Bible so far which states that life begins at conception, but I'd be happy to know is any Bible quote that supports the pro-lifer position at all. There's lots of contradiction in that book to discover.