In Hebrews 5:7, we are told of how Jesus prayed "in the days of His flesh." He "prayed with loud crying and tears to be saved from death". This is not referring to the last day of His life when He prayed in Gethsemane only. God's Word is exact when it says that He prayed like that "in the days of His flesh". "Days" refers to His entire 33½ years on earth. The death that Jesus prayed to be saved from (and from which He was saved, as this verse says) was certainly not physical death, but spiritual death (which results from committing even one sin). Jesus prayed that He might never sin even once. And He was so earnest about that, that His prayers for help were with loud crying and tears. That is why He never sinned. Many imagine that Jesus overcame sin because He was the Son of God. No. He overcame sin because He prayed with loud crying and tears to be saved from sin. He loved righteousness and hated sin so earnestly that He prayed so fervently - and His Father anointed Him with power, more than other believers who don't pray as earnestly as He did (Hebrews 1:9).
Most believers take sin casually and assume that they can never overcome sin, because they are human. But that is not the reason. The reason is that they don't pray with loud crying and tears to be saved from sin. It was to pray with loud crying and tears that Jesus often sought out lonely places for prayer (Luke 5:16). When we live in the city, it is difficult to find a lonely place. But I have discovered that I can pray with loud crying in my heart to God, without making any sound with my mouth, wherever I may be. I can cry out for purity in thought, word and deed. And if I fall into some sin, I want to have tears. Jesus never fell and yet He had tears. That really humbles me. Zeal for purity consumed Jesus and burned Him up. That's why He accomplished all the will of God on earth.
The fullness of the Holy Spirit brings a zeal for purity within us. Then we can follow Jesus' example. Jesus was never afraid of physical death. But He feared spiritual death and so He never wanted even the smell of sin in Him at any time. What was He praying for in Gethsemane, when He said that He didn't want to drink the cup? The cup He feared was the break of fellowship with His Father for 3 hours on the cross - when He would bear our sin. That is spiritual death. And Jesus hated sin, because it would break His fellowship with His Father.
But in Gethsemane, the Father told Him that He would have to accept that break in fellowship, if He was to save others from eternal separation from God in hell. And in His immense love for us, Jesus agreed to pay that heavy price. But all through His life He had resisted any break of fellowship with the Father - that would come through sin. The slightest smell of sin breaks fellowship with God immediately. If we value that fellowship, we will also pray with loud crying and tears that there should not be the slightest smell in us of bitterness, or spiritual pride, or impurity, or jealousy, or love of money, or hatred, or anything outside the perfect will of God.
It is because we don't have such a passion to live in God's perfect will, that we take sin so lightly. Holiness is not the major passion of most Christians. Their passion is usually some type of service for the Lord or for people in need. But that can be a worldly concept. Mary sought fellowship with Jesus while Martha sought to serve Him. And Jesus rebuked Martha saying that what Mary chose was the only thing necessary (Luke 10:42). It is holiness that makes our service effective.