"So then faith comes by hearing, and hearing by the Word of God". -Romans 10:17
It doesn't say faith comes from seeing and seeing by signs and wonders. Notice all throughout the Old Testament they simply believed the Word of God and it was counted to them as righteousness. It's described in Acts “For David himself never ascended into heaven, yet he said, ‘The LORD SAID to my Lord, “Sit in the place of honor at my right hand until I humble your enemies, making them a footstool under your feet.” He believed in the promise without seeing a thing, without having angels appear, without signs and wonders or ascending in to heaven...He simply believed in the Word and the One who had promised.
In the New Testament and even now we have seen the fulfillment of the Ultimate promise and yet we still seek to see more. We don't rest on the Word of God alone. He gives us His promises yet we seek a mighty miracle to sense His presence. He is faithful to deliver but are we looking for revelation of God and His character to glorify Him or to just make us feel good? Simply seeing His power displayed doesn't account for faith in Him...trusting His Word and His character is faith- believing in things not seen, in hopeful expectation knowing "He who promised is faithful!"
Let us rest in your sovereign Word Lord, like David- When You speak, let us trust in Your character and "walk by faith not by sight"!