In this passage of scripture David has started off with the words "fret not thyself because of evildoers", as a warning to those who would trust in temporal material things. We too will at times get caught up in trusting what we see, rather than what we know to be true in God. The word "trust" here means "to be confident, to be sure", and if we realy know God we will be assured of His provision. Because God's word is infallible we should have far greater expectation of Him than of modern inventions we trust in everyday! "my soul, wait thou only upon god; for my expectation is from him." Psalms 62:5. As we learn to trust in God to the point of anticipation, we will know without doubt or a second thought that we can totally depend upon Him!