The experience of Christ after His Baptism shall teach us, in the first place, how every Christian after he is baptized is enrolled in the army fighting against the crafty devil, who makes frequent attacks, and stirs up persecutions all the days of our life. If this bitter enemy does not succeed with his afflictions and temptations, to overcome Christians, he seeks to hang them upon the cross and to murder them as he did Christ.
This peril threatens all Christians. Nor ought we to expect anything else. If he did not spare Christ, but attacked Him so persistently, he will much less spare us, whom he knows to be weak and unprepared. We should therefore be ready to meet this danger when it comes, and learn of Christ how to repel the enemy. This however can only be done through faith in God and His Word. If we put on this armor and use it properly, we are secure against the devil and his attacks; but if we have it not, or are ignorant of its use, we are hopelessly lost, and will become a prey to our deadly enemy.
Every Christian should therefore earnestly read the Word of God and hear it preached, so that he may become well acquainted with it. Besides, we ought to pray incessantly to God to let His kingdom come unto us, to lead us not into temptation, but to deliver us from all evil. (Luther’s House Postil, Sermon for Invocavit, Volume 1, p. 257)

The Evangelist states three times that the disciples did not comprehend this prediction. They regarded His words as having some unusual and hidden meaning. They understood not a single word of these sayings, for they reasoned thus: This man performs so many miracles, He raises the dead, He gives the blind their sight, etc., from all of which it is evident that He will yet become a person of high position, for it is plain that God is with Him. Besides this, the Scriptures declare of Him that He shall have a glorious kingdom and exercise dominion over kings and princes on earth, while we, His servants, will also become princes and great lords. For who could in the least injure such a Person, who controls death and cures all infirmities with a single word? If He so desires, He can make the heathens His subjects and put beneath His feet all His enemies. Hence they dame to the conclusion that God loves Him too much to suffer any harm to befall Him; His sayings in regard to His sufferings and death must surely have another meaning. Thus reasoned the apostles in their simplicity.

God’s works are indeed incomprehensible, if they are considered before they are accomplished, but as soon as they are finished they are perfectly plain and intelligible. St. John states repeatedly that the disciples did oftentimes not understand the words of Christ, until the acts to which they referred had been accomplished. It is therefore necessary to have faith in the Word of God when He speaks He refers to matters far beyond the power of our comprehension; hence it behooves us to believe what He says, and then we shall fully experience and understand the true meaning of His words. (Luther’s House Postil, Sermon for Sexagesima, Volume 1, p. 218-219)