The passage has nothing to do with Suicide and everything to do with temptation. In order to understand the Gospel as it has been preserved one must understand first, what we fell from, and Second, what we aspire to rise to.
The temptations giving to Christ are the same as those outlined in 1 John 2:16 "For everything in the world--the lust of the flesh, the lust of the eyes, and the pride of life--comes not from the Father but from the world."
These 3 temptation presented to Christ make up those same temptations that were presented to Eve that caused our first parants to embrace sin and death.
Gen 3:5 But the serpent said to the woman, "you will be like God (Pride of life) knowing good and evil"
Gen 3:6 "So when the Woman saw that the tree was good for food" (lust of the flesh) It was a delight to the eyes (lust of the eyes) and the tree was desired to make one wise (Pride of Life) She took of its fruit and ate; and she also gave some to the her husband and he ate. (Disobediance)
Now when our Lord and Savior, after fasting for 40 days and nights was approached by Satan,he was hungry. His first temptation, withen his power was to take Rocks and turn them to bread. This desire of the flesh to eat must have been extreme, Christ had been fasting for 40 days and the creator of the world who made the universe out of nothing and could easily have changed a few rocks into bread.
It is important to notice here the method by which christ is teaching us, the 40 days represent the 40 years in exodus and Christ Humbling himself as God The Father humbled Isreal in the dessert, testing them to see wether they would keep his commandments or not. (See Deut 8:3) Where Isreal Failed, like our first parents, and we also fail, Chirst succeedes and concures the desires of the flesh.
Then Satan tempts Christ to show his power as it is written in Ps 91:11-12. He is effect is putting Christ to the test, "show me your power" and Christ says in effect "no" "You shall not tempt the Lord your God" He is humbled himself even more, not pridefully using the power given to him, but humbling himself and being obedient to his mission.
Then the Devil took him to a very High Mountain and showed him all the kingdoms of the world and all the Glory of them; and he said to him " all these I will give to you, you will fall down and worship me"
This is what Chirst came for, this is what his mission was, to bring the world back to God and restablish the Kingdom of David, the Church. The possibility of doing such a think without suffering the Cross, imagine the temptation any man might have with this offer, getting all things without suffering. This was the "lust of the Eyes" it is what chirst in his flesh desired, to avoid the pain of crucifiction and have all kingdoms under him. Lust of the eyes.
Chirst once again, as always in his life, was obedient to God the Father united in purpose.
The passages of Mathew 4: 5-6 have nothing to do with suicide or any other individual sin. It has to do with all sin as all sin can be attributed to the 3 charactoristics listed in 1 John 2:16.
Christ took Sin on himself, having suffered the greatest of temptations and concurring sin and death on the Cross. He did this perfectly as the spotless lamb. Our Goal as Christians is to emulate Chist in this by entering into his Passover, by uniting to him Through Baptism and the obedience of faith. Having been saved at baptism we as Christians in this "vale of tears" are continuelly tempted by the Lust of the Eyes, Lust of the Flesh and the Pride of Life. As we work to overcome these obsticales, the Church Christ founded gives us a means through it's sacrements to repent biblically and work towards our complete sanctification by uniting our efforts to Christ sacrifice on the Cross. Col 1:24.
Not suicide but the relationship lost in disobedience now restored through and by emulation of Christ through and Obedience of Faith.