What is the purpose of a 40-day fast? Why is the number 40 used instead of other numbers for such a fast? When can we practice a 40-day fast, and in what situations? There are only three men recorded in the Bible who fasted for 40 days and 40 nights.
To answer the first question, the purpose of a 40-day fast is a period of fasting lasting 40 days without food or water for the beginning of something, a new transition, a new appointment and assignment, and for other specific reasons such as divine experiences, repentance, spiritual upliftment, divine intervention, or divine preparation. It can be God-directed, inspired, and the leading of the Holy Spirit for someone to engage in this type of fasting for specific reasons known to God and the individual or ministry.
To answer the second question about why the number 40 is used instead of other numbers, the Bible offers no specific reasons; however, the number 40 has symbolic significance. The English word “forty” appears 158 times in 145 King James Bible verses, including 134 times in the Old Testament and 24 times in the New Testament. Generally, the number 40 represents a period of testing, trial, or probation. It can also denote a generation of humanity. It can also serve as a marker for the beginning of something new or entering a different phase.
Let’s examine three men recorded in the Bible who practised a 40-day fast.
Moses spent 40 days and nights on Mount Sinai twice (Exodus 24:18; 34:1–28) to receive God’s laws. The Book of Deuteronomy 9 summarises the incidents of Israel’s rebellion against God while Moses was on the mountain receiving the law and fasting for forty days and nights.
The next man is the prophet Elijah, who went 40 days without food or water at Mount Horeb after fleeing Jezebel, as described in 1 Kings 19:1–10.
The last person recorded in the Bible who undertook a 40-day fast is our Lord and Saviour Jesus Christ, who was led by the Holy Spirit into the wilderness and fasted for 40 days. After this, he was tempted by the devil, ushering in the beginning of his ministry. We can find this account in Mark 1:12–14, Matthew 4:1–4, and Luke 4:1–4. After Jesus’ forty-day fast and his confrontation and overcoming of the devil’s temptation, he emerges prepared and ready to begin his public ministry.
Why are these three men recorded as the ones who fasted for 40 days and 40 nights?
Could it be Moses, as the lawgiver, and Elijah, representing the prophets as a spokesman for God, of whom John the Baptist, who came in his spirit, prepared the way for the Lord? Jesus, who is the saviour of the world and the fullness of grace, brought grace and truth (see John 1:17).
All three men were once together on the Mount of Transfiguration (see Matthew 17:1; Matthew 17:1–13; Mark 9:1–13; Luke 9:27–36; 2 Pet. 1:16–18). Moses and Elijah, who appeared in glory, informed Jesus about his upcoming death on the cross for the salvation of humanity (see Luke 9:31). Both Moses and Elijah were significant in the life of Jesus.
How is Moses connected to Jesus? Well, Moses represents the law under the old covenant, and Jesus came to fulfil the law of Moses and to usher in a new covenant of grace. What about the connection of Elijah to Jesus? We can see this in the spirit of John the Baptist, the last Old Testament prophet, who prepared the way of the Lord and witnessed the light. Both Moses and Elijah represent a transition: the law and the prophets were proclaimed until John the Baptist, as it is written (see Luke 16:16), now that God has spoken to us through His Son (see Hebrews 1:2).
Moses, Elijah, and Jesus had a new, significant, and higher-level undertaking for God in their public ministries. In the case of Moses, he received the law, including the Ten Commandments, during two separate 40-day and 40-night fasts on Mount Sinai. For Elijah, the journey ahead was too great for him alone, but through divine experience, angelic encounters, and the great responsibility of anointing two kings — Hazel and Jehu — and his successor, Elisha, as prophet.
Moses, Elijah, and Jesus all experienced divine, spiritual, and supernatural presence, appearances, and directives. Moses was in the cloud of God’s presence; Elijah had angelic visitations; and the Holy Spirit led Jesus. After the temptation of Jesus, the angels ministered to Him, just as they ministered to Elijah. After fasting, Moses, Elijah, and Jesus gained new opportunities and a higher level of ministry.
As ministers, we can learn from Jesus the importance of following the Holy Spirit’s guidance and direction, seeking enablement when engaging in ministry, especially when practicing fasting. Such practice prepares us as ministers and equips us to conduct our public ministry powerfully, whether at the beginning of the year or when seeking ministry doors and opportunities.
When can we undertake a 40-day fast, and under what circumstances? First and foremost, ensure it is divinely guided and inspired for specific reasons.
Trying a 40-day fast may be appropriate — such as launching a new assignment, seeking repentance and renewal, or facing immense fear and unbearable crisis. Spirit-led timing matters more than personal aspirations, attention, ambition, or spiritual pride and power.
A forty-day fast can be practised to seek a divine encounter, revelation, covenants, the will of God, clarity from God, and as a marker of testing, transition, and new beginnings. If you are seeking clarity, covenant with God, and entering into and fulfilling your calling, a 40-day fast is suitable for such purposes.
When embarking on a new mission or spiritual undertaking with significant and higher responsibility entrusted to you, consider this practice.
For Moses, it was about receiving the law, which includes the 10 commandments. For Elijah, it was for deliverance and the anointing of significant figures. For Jesus, it marked the beginning of His earthly ministry.
Here are practical insights and applications as you initiate and are guided by the Holy Spirit to embark on a 40-day fast.
Let our fasting be with intention. While fasting, here are practical ways to firstly feed your spirit through Scripture and to keep your spiritual man alive through prayer as well. Practice solitude in your schedule, avoiding the easy trap of “killing time” with distractions. Avoid passing time with entertainment and fleshly indulgence during a fast. Practice sanctification during fasting so you don’t defile yourself with works of the flesh, and your prayer remains effective, preventing you from fasting in vain.
Immerse yourself in the Word, as the body loses calories, but the soul and spirit gain strength through the Word. As Jesus later answers the tempter with that same truth: a person does not live by bread alone but by every word that proceeds from the mouth of the Father.
The goal is to secure God’s presence and go in power as you continue and complete your fast. Ensure you prioritize securing God’s presence over simply putting on a performance. Constantly abide in the presence of God and seek His power so that you will be sustained during your 40-day fast, nothing else. Fasting without His presence becomes just a diet; fasting while abiding in His presence becomes fruitful.
Let fasting be what keeps you close to God, rather than just abstaining from eating and drinking or indulging in fleshly practices.
Note that even before, during, and after the 40 days of fasting, there will be divine encounters, experiences, and elevations. Before you start fasting, remember to do so with spirit-led directives and empowerment. During fasting, stay spiritually alert and alive. After you finish, guard your heart and mind by remaining in the Word, and continue to walk in the Spirit while also living a life of discipline, diligence, and righteousness. Be guided by the Spirit and walk in the Spirit to avoid temptations and old patterns that tend to resurface.
We can learn from Moses — after he completed his 40-day fast, what happened when he lowered his guard and discipline: Moses returned to find idolatry among his people, and God told him to go down and see what they were doing. Upon arrival, he was immediately angry and broke the tablets. The truth is, if you are not careful, spiritually sensitive, sound, and strong, you become vulnerable, fatigued, weak, and open to fleshly and satanic influences.
Post-fast, we can learn from Elijah that when fatigue and weakness take hold, you should wait on the Lord to provide what you need to continue your journey — whether spiritual and mental strength, physical nourishment, or reassurance and comfort.
One last insight from Jesus’ experience at the end of fasting is that you should expect both divine assistance and demonic resistance or temptations of the flesh. After fasting, a test from God and temptations from the devil are likely to occur.
Here are insights for before, during, and after the fast.
Before the fast, seek instruction for purpose; during the fast, stay alert, sensitive, and attentive; after the fast, listen for calls to action or instructions. Expect to hear from God before, during, and after the fast.
By Brahim M. Kallon (Wisdom Grace)
