John 17:18

“As you sent me into the world, even so I sent them into the world. And for their sakes I sanctify myself that they themselves also may be sanctified in truth.”

Just as Jesus was sent by the Father to ‘the world' as a light, to open its eyes, shake its complacency and make it aware of its evil (John 1:9 with John 3:16), so have the disciples been sent by the Son. But they will need the protection of ‘the truth' which can only come from God. Constancy in truth is the only way of combating the world and its ways.

‘For their sakes I sanctify myself.' On John 10:36 we are told that He was sanctified by the Father and sent into the world. In other words the Father set Him apart as His chosen means of delivering the world. How then will He now sanctify Himself ‘on their behalf '? The answer is that He is renewing His commitment to their salvation. They have been given to Him and as He begins a new phase of His ministry He is now unreservedly committing Himself wholly to the cause of their forgiveness, deliverance and safety, and this includes for Him the path of the cross.

There by His own will He will be ‘set apart to God' as a sacrifice, as a sin offering and as a whole offering pleasing to God on behalf of the disciples and on behalf of all who are given to Him (see Deuteronomy 15:19 for ‘sanctifying' referring to a sacrificial offering). But it includes far more, for having died for them He will be raised again to His throne and will ever live to make intercession for them (Hebrews 7:25; Romans 8:34) and be with them always to the end of the age (Matthew 28:20). He was setting Himself apart to God for the whole of His saving purpose.

‘That they also may be sanctified in truth.' Jesus has previously asked the Father to sanctify them (John 17:17). Now we learn that this can only be because of what He will do when He goes to the cross and as He makes intercession for them. Through His sacrificial death and continual intercession their sanctification in truth (being wholly set apart to God by their experience and knowledge of the truth) is made possible. Man can know the truth because He Who is the truth sanctified Himself on their behalf as an offering for sin. In His ‘setting apart', His own also are set apart.

So they will be ‘set apart to God' (sanctified) in and through God's truth, the truth of His word which Jesus has revealed to them (v. 17 with v. 8). What above all will make them objects of the world's hatred is that they have received and seek to pass on the truth of God. This benefit is something that they will enjoy because Jesus is deliberately “setting himself apart” (sanctifying himself) to suffering and glory. They too will be set apart to suffering and to glory, because they possess the truth. We note all through the prayer that Jesus is aware that as long as the truth abides in them everything else will fall into place. It is when we diverge from the truth or cease to pay it due heed that our problems begin.