God bless you if you have one child but I don't think anybody should have just one child. Everybody needs a sibling. I have siblings and I have so many amazing precious memories with my siblings. I don't know what I would do if I had been an only child.
The Word of God well understood and religiously obeyed is the shortest route to spiritual perfection. And we must not select a few favorite passages to the exclusion of others. Nothing less than a whole Bible can make a whole Christian.