Thank you for the opportunity to help you with your question!
The strength of the legislative branch is that it has the right to make the law.Congress the part of legislative branch which can make law it wants to make on any topic it wants.This gives congress a great deal of power.
The weakness of the Congress is that it can not really lead the people and get them a support a particular agenda, because the congress is so big and has so many members .No individual member can speak for the whole body.
Please let me know if you need any clarification. I'm always happy to answer your questions.