The wolf will swallow Odin, and that will be his death. But immediately afterwards Vidar will stride

The wolf will swallow Odin, and that will be his death. But immediately afterwards Vidar will stride forward and thrust one of his feet into the lower jaw of the wolf. He wears on that foot the shoe that has been assembled through the ages by collecting the extra pieces that people cut away from the toes and heels when fashioning their shoes. Thus those who want to help the Æsir should throw these extra pieces away. With one hand he takes hold of the wolf’s upper jaw and rips apart its mouth, and this will be the wolf’s death. 

Úlfrinn gleypir Óðin. Verðr þat hans bani. En þegar eftir snýst fram Víðarr ok stígr öðrum fæti í neðra kjöft úlfsins. Á þeim fæti hefir hann þann skó, er allan aldr hefir verit til samnat. Þat eru bjórar þeir, er menn sníða ór skóm sínum fyrir tám eða hæli. Því skal þeim bjórum braut kasta sá maðr, er at því vill hyggja at koma ásunum at liði. Annarri hendi tekr hann inn efra kjöft úlfsins ok rífr sundr gin hans, ok verðr þat úlfsins bani. (Prose Edda, ch. 51)