“This is to my Father’s glory”
So the reason becomes apparent why some branches are fruitless and therefore cut off – it’s because they do not remain in the vine (6). The warning of fruitless vine branches being burned (cf. Ezek.15:1-8) is not intended to make us guilty or fearful but to impress upon us the need to remain in him so that we will bear fruit for his glory.
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A further promise to answer the disciples’ prayers underlines the resources available when we remain in him (7). This saying is very similar to 14:13-14, for in each case Jesus speaks about the disciples’ fruitful ministry that will bring glory to the Father. Jesus doesn’t say here that the prayer must be “in my name” but rather “if you remain in me” (7), which likewise points to our union with Jesus as the basis of answered prayer. Similarly, the additional condition, “and my words remain in you”, refers to a life rooted in the whole teaching of Jesus.
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Jesus lived to bear fruit for his Father’s glory (17:4) and this continues through the fruit that he brings about in us (8; 14:13). We thus show that we are truly his disciples, for disciples put into practice the words and example of their master (13:35; cf. 8:31 "hold to" is the word meno i.e. remain).