Here Jesus teaches us that if we have unwavering and unchanging (mustard seed) faith we can say and then receive manifestation. The question arises: how do we build unwavering and unchanging faith? We build it by continually speaking aloud, and therefore, hearing The Word of God - written and spoken. Continually.
Saints, you're not subject to circumstances. No matter how seemingly impossible they appear in the natural. A tree is firmly planted with deep roots that spread out in various directions to keep it thriving and in place. But with faith and not doubting you can speak what you desire and have any tree of circumstances change to align with God's Original Design for your life.
Assess your life and determine which parts don't agree with the abundance Jesus made available. Find a Promise in The Written Word or one The Spirit of God spoke to you personally and speak it to build faith for manifestation. God's Word doesn't return void because it has sufficient faith inherently built in to cause manifestation to come. God already said yes and amen to all of His Promises, so to receive you must believe. If you say and hear yourself saying The Word enough times, your human spirit will increase in faith and that increase will pull God's Promise from the spiritual realm into the natural.
God's Word will not return void; it goes forward and produces everything He intends. God said He's given me everything I need for life and godliness. He said He supplies all of my needs according to His riches and glory through Christ Jesus. Because of God's provision I have extraordinary abundance and no lack anywhere in my life. It is so.