Christians are often challenged with prayer because humans are time-bound. According to Philippians 4:6 we should be anxious for nothing, but to live in prayer in all aspects of our spiritual lives including our spoken commands and elements of supplication. The fact is that even in His earthly, human form, Jesus acted through such strong belief in the power of God that His words yielded immediate favorable response. Jesus explained as much to His disciples at the withering of the fig tree. (Matt 21: 19-21)
If you own a car and wish to drive it, you do not call the manufacturer and ask for permission; you simply drive it. Likewise, God’s Word is given to the His righteous (Believers) to apply by command. You may elect otherwise to pray in belief for action through the applicable Word. However, if your experience applying the Word is insufficient, Christians find themselves in the throes of time (which is not infinite for our mortal bodies) and often suffer with concern and worry while waiting upon manifestations of righteous commands and petitions.
Yet, there is no scriptural support for “repeatedly commanding the fig tree to wither”. God’s approach is “light be… let no fruit grow on you ever again… Lazarus, come forth!…” These are examples of the delivery of God’s power through simple, single statements. Do likewise, followed by praise and thanksgiving (repeatedly as needed until seeing results without new petition).
However, as humans, the new tradesman and recently graduated attorneys do not acquire their licenses, new tools, and immediately take on the most challenging work possible. They generally lack appropriate know-how, and/or confidence. As such, the Bible recommends seeking assistance from the Elders, those with the relevant gifts, education, knowledge, skills and experience as needed. (e.g., James 5:14-15)
In any case, cast your cares, and acquire healing, provision, good relations, success, victory and all other manners of the blessings of God, without consideration of time.