it has been said that there is nothing as great as a mother's love. Some mother expressions mean just that.The phrase "mother lode" comes from mining.It means the place where the largest amount of gold can be found.But now ,the term"mother lode" means a rich supply of anything.For example ,you might say ,"She just graduated from collage and struck the mother lode with her new job!"
When we call something "the mother of all ",this means it is the biggest or best of something. Here is an example :"We are going to throw the mother of all parties this weekend .So you have to come!